Friday
February 12, 2016

Posts by Reiny

Total # Posts: 32,962

aacolsn
I had hoped your could continue, so we have 4 cases, prob(odd or perfect square) = 4/6 = 2/3
December 14, 2015

aacolsn
odds: 1,3,5 perfect squares: 1, 4 I count 4 possibilities, so .....
December 14, 2015

Math - not PACT
1. no restrictions, number of committees = C(7,4) = 35 2. 2 men and 2 women, number is C(4,2) x C(3,2) = 6(3) = 18 3. same set-up as #2, you try it 4. at least 2 women ---> 2 women, 2 men + 3women, 1 man = ... let me know what you got
December 14, 2015

maths
done, see your previous post under a different name http://www.jiskha.com/display.cgi?id=1450075351
December 14, 2015

rajput
done, see your previous post under a different name http://www.jiskha.com/display.cgi?id=1450075351
December 14, 2015

math
I will assume you want the radius of a circle that has an area of 154 cm^2. Why not state it properly? area = πr^2 πr^2 = 154 r^2 = 154/π r = √(154/π) = appr 7.00 cm
December 14, 2015

Math
I will assume that the pool is a cylinder. volume = π r^2 h = π(9)(2) = 18π What does the hose have to do with it? Was there supposed to be some rate of flow ?
December 14, 2015

math
make a simple sketch , to see that he completed a rectangle, so he must have traveled 20 km north or, suppose you don't see that right away: label his trips, AB, then BC, then BD from D draw a horizontal to meet AB at E so in right-angled triangle AED, AE^2 + 10^2 = 10^2 ...
December 14, 2015

Math
height-maple = (1/2)t + 4 height - birch = (2/3)t + 2 when they have the same height, (2/3)t + 2 = (1/2)t + 4 times 6, the LCD 4t + 12 = 3t + 24 t = 12 they have the same height 12 years from now subbing t = 12 into either equation yields (1/2)12+4 = 10 ft
December 13, 2015

Mathematics
the bases are both multiples of 2, so this is easy 4^(x-6)=2^(3x) 2^2)^(x-6) = 2^(3x) 2^(2x-12) = 2^3x then 3x = 2x-12 x = -12
December 13, 2015

Beacon house
I will assume that by "divided" you mean split up, and not actual division let one part be x, then the other is 39-x so (2/3)x + (3/4)(39-x) = 28 times 12 , the LCD 8x + 9(39-x) = 336 8x + 351 - 9x = 336 -x = -15 x = 15 so parts are 15 and 24 check: (2/3)(15) = 10 (3...
December 13, 2015

Mathematics
take logs of both sides log 3^(2x+1) = log 12 (2x+1)log3 = log12 2x+1 = log12/log3 2x = log12/log3 - 1 x = (log12/log3 - 1)/2 = .....
December 13, 2015

Advanced algebra
using our definitions, ar = 75 ar^4 = 3/5 divide the 2nd by the 1st: r^3 = 3/375 = 1/125 r = 1/5 back in ar = 75 a(1/5) = 75 a = 375 term7 = ar^6 = 375(1/15625) = 3/125 check my arithmetic
December 13, 2015

Finite Math
correct , small point ..... after 1.5 = e^(.07t) ln 1.5 = .07 lne .07t = ln 1.5 , since lne = 1 t = ln 1.5/.07 = 5.79.... don't put (lne=1) as part of your solution line,
December 13, 2015

math
treat the data as two ordered pairs of the type (s,c) where s is sales and c is commission. so you have (7000,700) and (8000,740) slope = (740-700)/(8000-7000) = 40/1000 = .04 so c = .04s + b , (compare with y = mx+b ) for (7000,700) 700 = .04(7000) + b b = 420 c = .04s + 420 ...
December 13, 2015

correction: math financial services
oops, I misread the question as investing 1000 every month, so amount = 1000(1.0025)^120 = $1349.35
December 12, 2015

math financial services
I will assume you are familiar with the basic compound interest formulas i = .03/12 = .0025 n = 10(12) = 120 amount = 1000( 1.0025^120 - 1)/.0025 = ....
December 12, 2015

Algebra
slope of given line = 8/3 so slope of perendicular line = -3/8 equation : y-3 = (-3/8)(x+2)
December 12, 2015

Math Help!
first case 1: a = 2b so a^2 + b^2 = 1^2 (2b)^2 + b^2 = 1 5b^2 = 1 b^2 = 1/5 b = 1/√5 one side is 1/√5, the other is 2/√5 you do case 2
December 12, 2015

Algebra
the first has a slope of -2, comparing it to y = mx+b 2nd: I will assume you meant: -5x + 10y = 5 10y = 5x + 5 y = (1/2)x + 1/2 so the slopes are 1/2 and -2, well, now you can be 100% sure they are perpendicular repeat for #2 remember , if the are parallel, the must have the ...
December 12, 2015

algebra
let the tens digit be x then the units digit is x+6 then the number is 10x + (x+6) = 11x + 6 sum of the digits = x + x+6 = 2x+6 11x + 6 = 2(2x+6) + 8 7x = 14 x = 2 the number is 28
December 12, 2015

Math
number of rides --- r 3r + 10 ≤ 50
December 12, 2015

math
i = .18/12 = .015 n = 30 PV = 4500( 1 - 1.015^-30)/.015 = ....
December 12, 2015

Math
Your thinking could be right, but what made you think it is, and why ?
December 11, 2015

math
2x - 2 + 8y dy/dx + 16dy/dx = 0 dy/dx(8y + 16) = 2 - 2x dy/dx = (2-2x)/(8y + 16) if the tangents are vertical, then their slopes are undefined, that is, the denominator of dy/dx = 0 8y + 16 = 0 y = -2 sub into original equation: x^2 - 2x + 8 - 32 + 1 = 0 x^2 - 2x - 23 = 0 x...
December 11, 2015

Math
$1.00/120 yes = $x/1,500,00 x = 1500000/120 = 12500 bob and champ both got the same correct answer. How did you ever get 9583 ?
December 11, 2015

math
no, not 30 look at bob's last equation of 2A = C/2 then C = 4A, sub that into A+C = 60 A + 4A = 60 5A = 60 A = 12 C = 48
December 11, 2015

Math
I will assume you mean 5^x = 50^(x+1) take logs of both sides log (5^x) = log (50^(x+1)) use rules of logs x log5 = (x+1)log50 x log5 = xlog50 + log50 xlog5 - xlog50 = log50 x(log5 - log50) = log50 x = log50/(log5 - log50) = appr -1.699 check: 5^-1.699 = .06493.. 50^-.699 = ....
December 11, 2015

Math TRUE or FALSE Help
Usually you do not have to worry about flipping until the last step, or until you have isolated the variable term on one side e.g. -3t + 7 ≥ 9 -3t ≥ 9-7 -3t ≥ 2 now we care about it. Whenever you multiply or divide by a negative number, we have to switch the ...
December 11, 2015

Geometry
1. vertex angle 2. angle ACB must also be x-3, because of isosceles triangle so : 4x-3 + x-3 + x-3 = 180 6x = 189 x = 31.5 so the angle is x-3 = 31.5-3 =28.5
December 11, 2015

Math
amount of water to be added --- x L .6(8) + 0x = .35(8+x) 4.8 = 2.8 + .35x .35x = 2 x = appr 5.71 L
December 11, 2015

Math, Algebra II
#3, you have an infinite number of solutions if, while you are solving, the variable drops out, and you end up with a true statement. your choice: 3/x + 2/x = 1 multiply each term by x 3 + 2 = x x = 5, one solution, so, wrong choice. correct answer: 4x/12 = 3x/9 x/3 = x/3 x/3...
December 11, 2015

probability
so you need one of the four aces --- C(4,1) = 4 plus one of the remaining 16 "ten" point cards = C(16,1) so prob of gettting 21 when dealt 2 cards = C(4,1)xC(16,1)/C(52,2) = 64/1326 = 32/663 or appr .048
December 11, 2015

math written assignment help
we do not do assignments here If you want to "cheat", there are websites that will help you with that for a fee.
December 11, 2015

intro to algebra written assignment help
ummmhh, I did this question for you when you posted it earlier. Always check back on your previous post before you re-post.
December 11, 2015

probability
so you want 2 right + 3 right + 4 right prob(correct guess) = 1/4 prob(wrong guess) = 3/4 prob as stated = C(4,2)(1/4)^2 (3/4)^2 + C(4,3) (1/4)^3 (3/4)^1 + C(4,4)(1/4)^4 (3/4)^0 = 6(1/16)(9/16) + 4(1/64)(3/4) + 1/256 = 67/256
December 11, 2015

probability
prob(miss none) = C(4,0)(.088)^0 (.912)^4 = ... prob(miss one) = C(4,1)(.088)(.912)^3 = .. add them up
December 11, 2015

probability
prob(tails) = 1/2 so if the coin is "fair", and the coin has no memory chip build in to know what has happened before, expected tails = (1/2)(500) = 250
December 11, 2015

pobability
prob(defect) = .16 prob(not defect) = .84 prob(at least 1 defective) = 1 - prob(none defective) = 1 - C(5,0) (.16)^0 (.84)^5 = 1 - .84^5 = appr.582
December 11, 2015

Maths
let the number of women be x then the number of men = 1.25x women to children = 8:5 = x : 5x/8 after 105 children come number of children = 5x/8+108 now : 1.25x : (5x/8+105) = 3 : 2 1.25x/(5x/8+105) = 3/2 15x/8 + 315 = 2.5x 1.875x + 315 = 2.5x x = 504 So we had 504 women, 630 ...
December 11, 2015

Finance
cash price = .85(3100) = 2635 So 2635 becomes the present value of the debt. are we doing this by simple interest or compound interest? by compound interest 270( 1 - (1+i)^-12)/i = 2635 this equation is very difficult to solve, and you need some special procedures. I will just...
December 11, 2015

Math
without graphing ..... "right end behaviour" to me means x ---> +∞ let's look at a somewhat large number e.g. x = 100 our expression is 100^3 - 1/e^100 my calculator says: 1000000 - 3.7 x 10^-44 = appr 1000000 wouldn't you say ? that is, as x gets ...
December 11, 2015

math
let the time be t hrs solve : 480t + 520t = 2000 btw, what is ml/hr ? wouldn't that be a rate a nurse would use to express the rate at which an infusion would be given?
December 11, 2015

Math
Get a "feel" for the numbers look at the |6-2x) = 2|3-x| as x ---->∞ , we end up with 2(∞) at the top , as x ---∞, the +1 becomes less and less signifiant as we approach 6(∞) so in effect we have 6∞/2∞ = 3 (my notation is really...
December 11, 2015

math
h=-16t^2+64t+512 we want h = 560 560 = -16t^2+64t+512 16t^2 - 64t + 48 = 0 t^2 - 4t + 3 = 0 (t-1)(t-3) = 0 it happened after 1 second AND after 3 seconds, once on its way up and then again on its way down
December 11, 2015

Math
(.6)/1 = 15/x solve for x
December 11, 2015

math
It is consonants not constants. In "mathcount" there are 3 vowels and 6 consonants So in 50 times the word, there are 150 vowels and 300 consonants so 150 more consonants
December 10, 2015

Simple Interest
amount invested at 9% --- x amount invested at 7% --- 20000-x .09x + .07(20000-x) = 1780 solve for x
December 10, 2015

math
6³√-512+13 = 6(-8) + 13 = -35
December 10, 2015

math
(x,y) ---> (-x, -y)
December 10, 2015

Finite Math
number of subsets of 11 elements = 2^11 = 2048 This includes the null set, equivalent to having no topping. Number of choices with at least one topping = 2048-1 = 2047
December 10, 2015

Finite Math
number of ways to choose 1 of 3 salads = C(3,1) = 3 number of ways to choose any number of 11 toppings, including choosing no topping = 2^11 = 2048 number of possible salads = 3(2048) = 6144 number of salads with Ranch and 4 dopping = 1x C(11,4) = 330 prop of event = 330/6144...
December 10, 2015

MATH
the nice thing about having the orientation of the inequality signs going the same way is that you can just perform the solution as it stands 3<5x-27<53 you are trying to get just "x" in the middle, so add 27 to all parts 30 < 5x < 80 divide by +5 6 < ...
December 10, 2015

MATH
This problem is from the textbook, but don't have explanation - only answer given
December 10, 2015

MATH
for your first question, you must be referring to http://www.jiskha.com/display.cgi?id=1449763017 from the point -x < 2 , or -1x < 2 remember to get x "alone" you divide by the coefficient of x, in this case -1 and of course since we divided by a negative, the ...
December 10, 2015

maths
amount of pure acid to be added --- x ml .15(800) + x = .32(800+x) solve for x
December 10, 2015

Math
C = 3.14(75000) = 235500 miles = 2.355 x 10^5 miles better answer using build-in calculator π = 23519.4 , off by about 119 miles
December 10, 2015

Geometry
x^2 + 4^2 = 5^2 x = 3 You should make a point to memorize the right-angled triangle with sides 3-4-5 as the smallest right-angled triangle with integer sides
December 10, 2015

Math
looks like an oops, you have given: dy/dt, then find dy/dt one of them should be dx/dt I will let you figure out which one. x^2 + y^2 = 20 2x dx/dt + 2y dy/dt = 0 x dx/dt = -y dy/dt when x = 4, 16+y^2 = 20 y^2 = 4 y = 2 now plug in our values into you have 3 of the 4 values to...
December 10, 2015

MATH
slip-up near the end, from: -x + 3 - 3 < 5-3 -x < 2 now divide by -1, not -x x > -2 your answer was correct, but I would deducted some marks
December 10, 2015

MATH
I see a problem in the first line, -7x> - 2(x - 30<10 has no closing brackets. In your third line your work shows that there was no need for a bracket. secondly, in a compound inequality the direction of the signs should be the same, e.g. -3 < x < 5 and the two ...
December 10, 2015

applilcations of trigonometry
Let AB be the height of the mountain, where A is at the top and B is on the line containing C and D let BD = x, and because of the 45° angle in the right-triangle ADB, AB = x then by Pythagoras AD = √2 x In triangle ACD , angle C 30, angle CDA = 135, leaving 15° ...
December 10, 2015

Science/Math
I will assume by "reproduced every 5 minutes" you mean "double every 5 minutes) so in one hour we would have a "doubling" taking place 12 times noon -- 1 5 minutes later -- 2 , or 2^1 --- first doubling 10 minutes later --4 or 2^2 --- 2nd doubling .. ...
December 10, 2015

Math
first of all let's clean up the equation multiply each term by 14 , the LCD -12x - 7y = 6 , or even nicer.. 12x + 7y = -6 slope = -12/7 , which leans to the left ruling out A, B, and C. A is horizontal and B and C have positive slopes this leaves D I will leave it up to ...
December 10, 2015

math
speed of slower car --- x km/h speed of faster car ---- x+5 km/h When they meet, each will have gone for 12 hrs 12x + 12(x+5) = 288 24x = 228 x = 9.5 slow car went 9.5 km/h, the faster went 14.5 km/h check: 12(9.5) + 12(14.5) = 288 , the answers are correct mathematically A ...
December 10, 2015

Algebra
It said she wants to "make at least $120" To me that means that your relation should contain > 120 or ≥ 120 This automatically ruled out 2 of the 4 statements, and in D she limits her sales to $140 A quick check will show that the 3 points given for 6x + 10y...
December 10, 2015

jamindan national high school
smaller angle --- x larger angle -----x+20 complementary angles add up to 90° so ....
December 10, 2015

math
let the length be 9x and the breath be 5x given: 5x = 360 x = .... then find 9x
December 10, 2015

algebra 1
width --- x ft length --- x+6 ft 2(x + x+6) = 360 solve for x
December 10, 2015

Math
A plan1-cost = .15m + 195 plan2-cost = 270 where m is the number of miles B and C, just plug in the mileages D set .15m + 195 = 270 and solve
December 10, 2015

Math
I did this for you on Monday http://www.jiskha.com/display.cgi?id=1449541115
December 10, 2015

math
n + n+1 = 4 2n = 3 n = 1/5 , but n is to be a whole number, so no solution to your problem e.g. 1+2 = 3 2+3 = 5 nothing equals 4 (the sum of two consecutive whole numbers is always odd, think about it)
December 9, 2015

Trigonometry
the x=5, y=2 and r^2 = 25+4 = 29 r = √29 sinØ = 2/√29 + 5/√29 = 7/√29
December 9, 2015

sun shine
make a sketch. On mine I sketched a rectangle of side 40 and height h, with two right-angled triangles on each end On the left I had a hypotenuse of 39 , a height of height, and a base of x On the right , I had a hypotenuse of 56, a height of h and a base of 25-x so h^2 + x^2...
December 9, 2015

Pre-Algebra
I see 8x+11-4-27 -11/-11 8x=4x+38 +4x 4x 12/12x=38/12 = 1 1/3 as mathematical gibberish, and it has nothing to do with the initial question. does this have something to do with http://www.jiskha.com/display.cgi?id=1449711876 which I answered.
December 9, 2015

Calculus
C ' (x) = - x^-3 or -1/x^3 when x = 5, C ' (5) = -1/125 when x = 8 , .......
December 9, 2015

MATH
Polygons with 3 vertices, (triangle) = C(7,3) = 35 polygons with 4 vertices = C(7,4) = 35 polygons with 5 vertices = C(7,5) = 21 polygones with 6 vertices = C(7,6) = 7 polygons with 7 vertices = 1 add them up
December 9, 2015

Algebra
usually you would find x's and y's y = 4a + 27 16x - 2y = 22 -2y = -16x + 22 y = 8x - 11
December 9, 2015

Math-Algebra
If you are asked to use substitution, usually one of the equations has a variable with coefficient of 1 e.g. 3x + y = 8 solve that equation for y (or x) and sub it into the other equation. e.g. 5x - 7y = 59 x + 4y = 1 from the 2nd, notice that the x term has a coefficient of 1...
December 9, 2015

Maths
unit digit --- x tens digit --- y x+y = 14 y = 14-x 2y - x = 1 2(14-x) - x = 1 28 - 2x - x = 1 27 = 3x x = 9 then y = 14-9 = 5 the number is 59
December 9, 2015

Math
the scale means 1 inch ---> 1,500,000 inches 2.625 inches = 2.625(1500000) inches = 3937500 inches = 328125 ft = 62.14 miles or appr 62 miles Tell your teacher that schools in Canada have been using the metric system since the 70's and to get rid of those old textbooks.
December 9, 2015

Grade 10 Math
use a simple ratio: 30/10 = x/60 , notice 60 minutes = 1 hr x = 60(30/10) = 180 ft you do the conversion to yards, etc
December 9, 2015

Math
even integers are 2 apart, so if we let the first be n the 2nd be n+2 the rd be n+4 now just translate the English into Math "3 times the 1st " ---- 3n "is equal to" ---> = "2nd added to the 3rd plus 38" ---> (n+2) + (n+4) + 38 3n = n+2 + n+...
December 9, 2015

MATHMATHICS
If a line passes through a given point, then the coordinates of the point must satisfy the equation for y = x^2 + bx + c for (3,14) --> 14 = 9 + 3b + c , or 3b + c = 5 for (-4,7) --> 7 = 16 - 4b + c , or -4b + c = -9 I would subtract the two equations, 7b = 14 b = 2 plug...
December 9, 2015

Math
Number 1 should have been marked correct for the 3 units given, only the gallon would make sense
December 9, 2015

Math
All 10 are correct, good job
December 9, 2015

MATHS
let the two numbers be n and n+1 then: n^2 + (n+1)^2 = 313 2n^2 + 2n - 312 = 0 n^2 + n - 156 = 0 (n+13)(n-12) = 0 n = 12 or n + -13, but n> 0 the numbers are 12 and 13
December 9, 2015

Math
x = 100(1/x) x^2 = 100 x = ± 10
December 9, 2015

Algebra worksheet
The whole assignment seems to deal only with one simple concept, a direct variation Sometimes text or your notes have definitions that are difficult to understand. Here is the definition that is easy to understand: A direct variation gives you an equation that contains no ...
December 9, 2015

math
length of Roberts wire --- x length of Maria's wire ---- 10-x x = (2/3)(10-x) times 3 3x = 2(10-x) 3x = 20 - 2x 5x = 20 x = 4 take over
December 8, 2015

Algebra
Can you find the length and width of the inner rectangle? can you find the area of the original rectangle? can you find the area of the inner rectangle? wouldn't original rectangle - inner rectange give you the area of the walkway?
December 8, 2015

Algebra-Perimeter
side of triangle -- x perimeter of triangle = 3x side of square = x+4 perimeter of square = 4(x+4) = 4x + 16 4x+16 - 3x = 28 x = 12 State conclusions
December 8, 2015

help me math
just did it for you. Have patience, look back before reposting the same problem
December 8, 2015

college algebra help******
We don't do assignments here. You will have better luck dealing with one question at a time, and letting us know where your problems lie.
December 8, 2015

Trig
retype in proper form. Are we solving or proving an identity?
December 8, 2015

Trig
You clearly did not even look at my previous post in reply to a similar question.
December 8, 2015

math
first you need the slope m m = (4-2)/(5-8) = -2/3 so y = (-2/3)x + b but (5,4) lies on it, (we could use (8,2) ) 4 = (-2/3)(5) + b 4 = -10/3 + b b = 22/3 y = (-2/3)x + 22/3 I usually check my equation by using the point NOT used to find the equation. e.g. for (8,2) LS = 2 RS...
December 8, 2015

math
Don't really know what you are saying, but ... If there is no y-intercept, then you must have a vertical line, and the equation would not take the form y = mx + b To have a vertical line, the m , or the slope would be undefined, which is not a numerical value If b = 0, ...
December 8, 2015

Geometry
Depends which are the two equal sides case1: 5x - 12 = 3x 2x = 12 x = 6 then the sides are 18, 18 and 26 case2: 3x = x+20 2x = 20 x = 10 then the sides are 30, 30 and 38 case3: 5x-12 = x+20 4x = 32 x = 8 then the sides are 24, 28 and 28
December 8, 2015

Trig
see my previous comment about trig names RS = csc^2 Ø tan^2 Ø - 1 = 1/sin^2 Ø(sin^2 Ø/cos^2 Ø) - 1 = 1/cos^2 Ø - cos^2 Ø/cos^2 Ø = (1 - cos^2)/cos^2 Ø = sin^2 Ø/cos^2 Ø = tan^2 Ø = LS
December 8, 2015

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