Monday
January 23, 2017

Posts by Reiny

Total # Posts: 37,369

math
0.61m-1.51m=9 -0.9m = 9 m = -9/.9 m = -10
September 23, 2016

math
n-2= (10n+4)/2 n-2 = 5n + 2 -4 = 4n n = -1
September 23, 2016

Math
Easier to tell once we solve the inequation y-9>2y-2 y - 2y > -2 + 9 -y > 7 y < -7 so which numbers are less than -7 ?
September 23, 2016

math
discount = 275-220 = 55 percent of discount = 55/275 = .....
September 23, 2016

OOPS - GEOMETRY
let's back up a bit here. I set up a ratio of 1:3, thus splitting the line into 4 parts SHOULD HAVE BEEN RATION 1:2 let P(x,y) divide AB into 1:2 so for the y: (y+3)/(1-y) = 1/2 2y + 6 = 1 - y 3y = -5 y = -5/3 for the x: (x+6)/(3-x) = 1/2 2x + 12 = 3-x 3x = -9 x = - 3 , so...
September 23, 2016

GEOMETRY
let P(x,y) divide AB into 1:3 so for the y: (y+3)/(1-y) = 1/3 3y + 9 = 1 - y 4y = -8 y = -2 for the x: (x+6)/(3-x) = 1/3 3x + 18 = 3-x 4x = -15 x = -15/4 , so P is (-15/4, -2) check so far: http://www.wolframalpha.com/input/?i=plot+%7B+(-6,-3),+(3,1)+,+(-15%2F4,-2)%7D notice ...
September 23, 2016

Algebra 2
just divide both sides by pr s/(pr) = prt/(pr) s/(pr) = t
September 23, 2016

calculus help
find dy/dx 3y^2 dy/dx = 6x dy/dx + 6y - 3x^2 (dy/dx)(3y^2 - 6x) = 6y - 3x^2 dy/dx = (6y - 3x^2)/(3y^2 - 6x) = 0 for a max/min 6y - 3x^2 = 0 y = x^2/2 sub that back into the original: (x^2/2)^3 = 6x(x^2/2) - x^3 - 1 x^6/8 = 3x^3 - x^3 - 1 x^6/8 = 2x^3 - 1 x^6 = 16x^3 - 8 let x^...
September 23, 2016

Maths
well, if 2 cm ---> 5 km 1 cm ---> 2.5 km then 8 cm ----> .......
September 23, 2016

Math
f(4) = 200 e^(-.3(4)) = ... for 2nd part: half of 200 is 100 100 = 200 e^(-.3t) .5 = e^(-.3t) take ln of both sides ln .5 = -.3t lne , remember lne = 1 etc
September 23, 2016

Geometry and algebra
Don't understand your word salad, but it looks like you have a rectangle with a circle in it. No idea where the shaded region is, but ... find the area of the rectangle find the area of the circle Assuming the shaded region is the part outside the circle within the ...
September 23, 2016

Trigonometry
Assuming those directions are 75° and 165°. and ignoring the b) North , whatever that means you have a very simple problem. I made a sketch with O the port, P as its first position and Q as its final position. With some simple geometry you should see that angle P is a ...
September 23, 2016

Math
what is 2(50) - 40 ?? Btw, we mow lawns, not moe them we use a lawn-mower, not a lawn-moer
September 23, 2016

math
what is 2/3 of 60 ?
September 23, 2016

math
original fraction ----- (x-3)/x new fraction = (x-3 + 4)/(x+4) = (x+1)/(x+4) then (x+1)/(x+4) = 3/4 4x + 4 = 3x + 12 x = 8 the original fraction was .....
September 23, 2016

Math
You are choosing 3 of 4, which is C(4,3) = 4 or think of it this way: each choice you leave out a different colour, there are four colours to leave out. So four choices.
September 22, 2016

Thanks Steve - Algebra
Yup, my oops. Thanks
September 22, 2016

Algebra
how about multiply each term by 3, and look, no more fraction: -6x + y = 4 now replace your x with -3 -6(-3) + y = 4 18 + y = 4 y = 4 - 18 = -14
September 22, 2016

Math
look at a number line. The number farthest to the left is the smallest, so -8.2 <---- smallest etc
September 22, 2016

Finance
I will assume there will be 216 monthly deposits (18x12). The formula I will use assumes that the payment is made at the end of the month, but with that many payments and that trivial rate of interest it will be very little difference. i = .003/12 = .00025 p (1.00025^216 - 1...
September 22, 2016

math11
ezra's age in 2001 ----x lior's age in 2001 ----- 4x in 2003 ezra --- x+2 lior ----- 4x+2 4x+2 = 2(x+2) continue ....
September 22, 2016

mathematics
3/5 of 8 = 24/5 so what percent of 4 is 24/5 ---> 24/5 ÷ 4 = (24/5)(1/4) = 24/20 = 1.2 or 120 %
September 22, 2016

math
So the distance between them is changing at 64-53 or 11 mph time for that distance to reach 17.5 miles = 17.5/11 hrs = 1.59 hrs or appr 1 hour and 35 minutes.
September 22, 2016

math
x^3-(p+q-r)x^2+(pq-pr-qr)x+pqr If it factors, the p, or q, or r must be solutions to x^3-(p+q-r)x^2+(pq-pr-qr)x+pqr = 0 let f(x) = x^3-(p+q-r)x^2+(pq-pr-qr)x+pqr try x = p f(p) = p^3 -p^2(p+q-r) + (pq - pr - qr)(p) + pqr = p^3 - p^3 - qp^2 + rp^2 + qp^2 - rp^2 - prq + pqr = 0 ...
September 22, 2016

Math
if 1 gallon give you 15.1 miles 2 gallons will give you 2(15.1) or 30.2 miles 7 gallons will give you 7(15.1) miles .. 24 gallons will give you ....
September 22, 2016

honors algebra 1
correct, I was following that format in (3,1) , x = 3, y = 1 so in y = x - 4 I let LS = y = 1 RS = x - 4 = 3-4 = -1 so the point (3,1) does NOT lie on y = x-4
September 22, 2016

honors algebra 1
I can't see which choices you made. simply , sub each point into the equation to see if it works e.g. in #1 (3,1) into y = x - 4 LS(left side) = 1 RS = 3-4 = -1 , looks like that one didn't work.
September 22, 2016

math
I will assume you made monthly payments let that payment be p i = .08/12 = .00666... n = 36 PV = 10300 p( 1 - 1.00666..^-36)/.00666.. = 10300 solve for p (hint: it is around 320 ) take it from there
September 22, 2016

mathematics
Bob showed you that T = 7, then B = 11 there are 7 trikes and 11 bikes check: total is 18 vehicles 7(3) + 11(2) = 21 + 22 = 43 Bob's answer is correct
September 22, 2016

math
only true if you meant: tanA/(secA+1) + cotA/(cosecA+1)=cosecA+secA -secAtanA LS = (sinA/cosA)(cosA) + 1 + (cosA/sinA)(sinA) + 1 = sinA + cosA + 2 RS = 1/sinA +1/cosA + (1/cosA)(sinA/cos) = 1/sinA +1/cosA + (sinA/cos^2 A) = (cos^2 A + sinAcosA + sin^2 A)/(sinAcos^2 A) = (1 + ...
September 22, 2016

maths
term8 = a+7d term2 = a+d a+7d = 5(a+d) a + 7d = 5a + 5d 2d = 4a d = 2a term5 = a+4d = 8 a + 4(2a) = 8 9a = 8 a = 8/9 ---> d = 16/9 terms are: 8/9, 24/9, 40/9, 56/9, 72/9, 88,9, 104/9, 120/9, ... carry on check: 5 times the 2nd = 5(24/9) = 120/9 which is term 8
September 22, 2016

Math
Please restate in English using proper grammar and punctuation.
September 22, 2016

math 101
Writeacher, nice answer showing how mathematicians often assume what to them appears obvious, resulting in poor wording of the question. number of ways to choose 7 from 10 = C(10,7) = 10!/(3!7!) = 120
September 22, 2016

MATH HELP
I don't see your choices, so I can't check
September 22, 2016

MTH HELP
You did not indicate what your choices are, so how can I check your work?
September 22, 2016

Math
In what system do you get .5 marks for a wrong answer? Did you mean .5 marks are deducted for a wrong answer? then what is 2(42) - 35(.5) ?? This question makes no sense. If there are a total of 100 marks, and each correct answer is worth 2 marks, then there could only be a ...
September 22, 2016

math algebra
speed of current --- x mph distance ---- d miles time to go downstream = d/(20+x) time to go upstream = d/(20-x) d/(20+x) = (3/5)d /(20-x) divide both sides by d 1/(20+x) = 3/(5(20-x)) cross-multiply 60+3x = 100 - 5x 8x = 40 x = 5 the speed of the current is 5 mph check: ...
September 22, 2016

8th Grade Math-exponents
books have been know to be wrong, as do most teachers and students. from the way you typed it, the simplified answer is (x/2)^7 / (x/2)^6 = x/2 John1's explanation is correct
September 21, 2016

GOVT JUNIOR COLEGE
When your parrot has flown away
September 21, 2016

@ Steve - Math - check answer
Wow, simultaneous posting times. I wish there was a way to know if a fellow tutor is working on the same problem at the same time as another tutor. This would eliminate the unnecessary time that both spent on the solution. The only positive is that in most cases we end up with...
September 21, 2016

Math - check answer
To cut through the word salad of this question, we know: when t = 0 , f = 58000 when t = 2, f = 92800 , and our model is an exponential function the default base of an exponential equation is e, f = c e^kt , were c is the starting number so we can start with: f = 58000 e^kt ...
September 21, 2016

Math
true, sinx = 4 has no solution. Many equations have extraneous roots, so they don't become part of your solution set In this case the only factor that works is 3sinx + 1 = 0 sinx = -1/3 so x is in the third or fourth quadrant according to the CAST rule the angle in ...
September 21, 2016

Math
if you meant: (3/4)^3 , then = (3/4)(3/4)(3/4) = 27/64
September 21, 2016

Math
(3/4)(3) = 9/4 or 2 1/4 line up 3 sets of 3 quarters now count the quarters, you should see 9 quarters or $ 9/4, or $2 dollars and 1 quarter, or $2.25
September 21, 2016

ss
Reed, the tundra in my Canada north of Yellowknife has very little vegetation and is very cold for much of the year.
September 21, 2016

ss
The tundra would also fall within the categories stated in the question.
September 21, 2016

GOVT JUNIOR COLEGE MATHS
The exterior angles of a regular polygon are all equal, and for a polygon of n sides, they are 360/n ° each. So .....
September 21, 2016

Math
use your rules for powers recall: x^a × x^b = x^(a+b) (x^a)^b = x^(ab) x^-a = (1/x^a) ((4/x)^(n-m))×((2x^2)^m) = ((2^2 x^-1)^(n-m))×((2x^2)^m) = 2^(2n-2m) x^(m-n) × (2^m x^2m) = 2^(2n-m) x^(3m-n) check my arithmetic
September 21, 2016

Maths
You have in front of you the famous 1 - √3 - 2 right-angled triangle, with angles 30°, 60° and 90° respectively. You can easily find RP = 1 using Pythagoras. I strongly recommend that you memorize this for any future work in trig. (I always reminded my ...
September 21, 2016

Math
I don't know how Steve got those numbers, it comes out to appr 125.3 I made a sketch. I extended BC to E so the DE is an altitude and triangle DCE is right-angled. I let CE = x and DE = h x^2 + h^2 = 100, and (x+15)^2 + h^2 = 400 subtract them (x+5)^2 - x^2 = 300 30x + 225...
September 21, 2016

algebra
"y varies directly as x" ---> y = kx if x=24, y= 8 8 = 24k k = 8/24 = 1/3 <---- answer so y = (1/3)x "y varies inversely as x" ---> y = k(1/x) = k/x for x=4 and y=8 8 = k/4 k = 32 <---- the constant of variation y = 32/x Claire was right.
September 21, 2016

Math
volume = 12(12)(200) cm^3 = 28800 cm^3 or .12(.12)(2) m^3 = .0288 m^3
September 21, 2016

Algebra 1
g(X) = x^2 - X g(2) = 4 - 2 = 2 g(2)^2 -2 - (2)-2 = 4 - 2 - 2 - 2 = -2
September 20, 2016

Math
sketch a line making an angle of 27° with the horizontal. Label the length of the tree's shadow on that line as AB, with B the foot of the tree. Let the top of the tree be C (so we need BC) from A draw a horizontal and let CB extended hit that horizontal at D in the ...
September 20, 2016

math
your wording makes no sense. Did you mean 1/53 of Michael's age?
September 20, 2016

math
for both of your posts I got "file not found"
September 20, 2016

math
360 is the total of the trees number of oak trees --- 5x number of mapes ------ 7x 5x+7x = 360 12x = 360 x = 30 number of maples = 7x = 7(30) = 210 (oaks would be 150, for a total of 360 )
September 20, 2016

Mathematics
simple tangent ratio height/42 = tan36° solve for height
September 20, 2016

Maths Mensuration
first find the dimensions breath (width) ---- x length ----------- 2x 2x + 4x = 240 6x = 240 x = 40 so the park is 40 m by 80 m area of whole park = 3200 m^2 make a sketch to see that the area of the region inside the path is 36 m by 76 m area of that part = 2736 m^2 so area ...
September 20, 2016

Maths
looks quite simple, draw your Venn diagram, label the intersecting circles sw, s and f place 5 in the intersection of the 3 circles. Now look at the intersection of th sandwich and fruit, it says 7 but you already placed 5 into part of that region, so that leaves 2 for the ...
September 20, 2016

Maths Profit and Loss
solve for x, the production cost (1.06)(1.08)(1.1)x = 14741
September 20, 2016

Maths Congruence
It has to be the contained angle
September 20, 2016

math
rationals and integers
September 20, 2016

maths
10 men to build a 1 house in 6 months 10 men to build a 1/6 house in 1 months 10 men to build a 4/6 house in 4 months 1 man to build a 4/60 house in 4 months 60/4 men can build 1 house in 4 months 15 men can build 1 house in 4 months or more simply it takes 60 man-months to ...
September 20, 2016

Math
a = 5.4 v = 5.4t + c but v = 0 when t = 0 , so c = 0 v = 5.4t s = 2.7t^2 + k but s = 0, when t = 0 , so k=0 2.7t^2 = 145 t^2 = 145/2.7 t = ....
September 20, 2016

maths
NO first of all you are using x incorrectly (in the third last line x = 8,2584, and in the last line x = 41292, which is a contradiction) furthermore, we place a comma after groups of 3 digits for easier reading, not groups of 4 digits. furthermore #2, if the height is 6 cm, ...
September 20, 2016

algebra 1
find √7 and √3 on your calculator, change -7/4 to a decimal Now you should be able to tell their relative size
September 20, 2016

Math
to solve: 2x+c = 8-2x-x^2 x^2 + 4x + c-8 = 0 to have y = 2x+c to be a tangent, there can be only one real root of the quadratic so b^2 - 4ac = 0 16 - 4(1)(c-8) = 0 16 - 4c + 32 = 0 4c = 48 c = 48/4 = 12 check with Wolfram: http://www.wolframalpha.com/input/?i=y%3D2x%2B12,+y%...
September 20, 2016

Algebra
jorges ---- x years brother ---- 3x - 4 solve x + 3x-4 = 24 and sub back into my definitions.
September 20, 2016

Math
both are good examples
September 20, 2016

Math
what is .25(40) ?
September 20, 2016

correction - Math
actually I misread the question, Now I see that 12x = 48 x = 4 so we have 48 soccer balls and 60 baseballs (even easier than before)
September 20, 2016

Math
soccer balls --- 12x baseballs ------ 15x solve 12x+15x=48 x = 16/9 soccer balls ---- 12(16/9) = 64/3 ???? bogus question! both soccer balls and baseballs must be whole numbers.
September 20, 2016

Math
Since the ball is returned, these are independent events prob(not white) = 12/17 we want this 4 times in a row, so prob(your event) = (12/17)^4
September 20, 2016

maths
Did you sketch your Venn diagram? The missing part is the intersection of all 3, label it x Now look at the intersection of A and C, it must be 34. But you already have x accounted for in the intersection of all 3. So label the part in A and C, but not B as 34-x 36 study A and...
September 20, 2016

Math
It takes 1 team 5 minutes to clean 200 yards It takes 2 teams 5 minutes to clean 400 yards (assuming they don't get in each other's way) 1760/400 = 22/5 It takes 2 teams 5(22/5) minutes to clean 1760 yards <b<It takes 2 teams 22 minutes to clean 1 mile (DonHo'...
September 20, 2016

Math
What she is referring to is this: 337 = 300 + 30 + 7 so the value of the 3 in the tens place is 1/10 the value of the 3 in the hundreds place
September 19, 2016

Math
what does x4x mean? did you mean x^(4x) ?
September 19, 2016

Math 6th grade
numbers which when divided by 4 leave 3: 7 11 15 19 23 27 31 35 39 43 ... numbers which when divided by 5 leave 3: 8 13 18 23 28 33 38 43 48 ... numbers which when divided by 6 leave 1: 7 13 19 25 31 37 43 ... ahh, 43 is in all 3 lists, so ....
September 19, 2016

math
P = I^2 R plug in your given 40 = I^2 (3) 40/3 = I^2 I = √(40/3) = ...
September 19, 2016

Math
20 hundredths = 20(.01) = .2 2 thousandths = 2(.001) = .002 What are you going to tell Janice ?
September 19, 2016

algebra
h = 15j j = h/15
September 19, 2016

Math
C = 560 + 40x inverse: interchange the variables x = 560 + 40C C = (x -560)/40 = g^1(C)
September 19, 2016

Math
4(log(x)+5)=6 log x + 5 = 6/4 = 1.5 log x = -3.5 x = 10^(-3/5) = .... I get x = appr .000316
September 19, 2016

Math
93=12(2)^p 2^p = 93/12 = 31/4 take logs log 2^p = log (31/4) p log2 = log31 - log4 p = (log 31 - log 4)/log 2 = you push the buttons.
September 19, 2016

Math
blue cars --- x red cars ---- 2x yellows ----- (1/3)2x = 2x/3 x+2x+2x/3 = 33 times 3 3x+6x+2x=99 take over
September 19, 2016

Math
prob(white, then green) = (7/50)(4/49) = ...
September 19, 2016

Algebra
Wouldn't the temperature be between 14 and 22 ? so 14 ≤ T ≤ 22 you were on the right track with |T - 18| but you should have said: |T - 18| ≤ 4 then T-18 ≤ 4 and -T + 18 ≤ 4 T ≤ 22 and -T ≤ -14 ----> T ≥ 14 the connective...
September 19, 2016

Algebra
I would double the first and get: 4x + 6y = 8 5x + 6y = 7 subtract them: x = -1 sub back into one of the originals to get y
September 19, 2016

Algebra
John's error, after multiplying by 3 , should be 15x + 12y = -42 , John had +42
September 19, 2016

Math
"the hundred digit is greater than 7" ---> 8XX or 9XX "the tens is one more than the hundreds digit" ---> 89X "the ones digit is less than 2" --- 890 or 891 "If my clothes are like this" ???????
September 19, 2016

Math
If t represents the hours she babysits, Charge = 8t + 2.50 that is, your equation would be 8t + 2.50 = 30.50 I have not clue why Smiley is multiplying the hourly fee by the cost of the bus ride. Smiley's reply is gibberish.
September 19, 2016

Physics needed - maths help me
need physics properties
September 19, 2016

Math
Surely you meant: b(t) = 50t/(t+1) or else the t's would just cancel b(1) = 50(1)/(1+1) = 51/2 or 25.5 b(2) = 50(2)/(2+1) = 100/3 = ... b(5) = 50(5)/(5+1) = 250/6 = .. etc
September 19, 2016

Maths
breath or width ---- x m length ------------- x+5 m given: x(x+5) = 84 x^2 + 5x - 84 = 0 (x -7)(x + 12) = 0 x = 7 or x is a negative width is 7, length is 12, so perimeter is .... ?
September 19, 2016

math
Oh my goodness! Steve showed you that 1 textbook weighs 1 kg so how much will 5 textbooks weigh ?
September 19, 2016

Math
solve for x (2/5)x = 80 (If she finished 3/5 of the book, then 2/5 remain to be read)
September 19, 2016

Math
I don't have that function on mine, so I have to actually think it through and do the math prob(a four) = 1/4 , prob(not four) = 3/4 at most 6 fours means: 0 four, 1 four, 2 fours, 3 fours, 4 fours, 5 fours, 6 fours. prob(your event) = C(22,0)(3/4)^22 + C(22,1)(1/4) (3/4)^...
September 18, 2016

math
easily done with a sketch across y = 3 (0,0) ---> (0,6) across the x-axis (0,6) ---> (0, -6) (remember that the equation of the x-axis is y = 0
September 18, 2016

Math
hour hand: 8:00 am to 11:30 am is 3.5 hours. on the face of a standard clock this is 3.5/12 or 7/24 of a rotation, thus 105° or 7π/12 radians minute hand from 8:00 am to 11:30 am the minute hand will have made 3.5 rotations or gone through 1260° or 7π radians
September 18, 2016

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