# Posts by steve

Total # Posts: 53,594

Math
let's say you have exactly twice as many bars as he. So you have 1340 and he has 670 So, as long as you have at least 1340, but fewer than 2009 bars, he has some, and you have at least twice as many.

Math
16 + 10*2 / 5 = 20

Math
Oops. That's 490, as Ms. Sue said, but the answers stay the same.

Math
a work day has 15+60*7+55 = 485 minutes (1) 485/35 = 13.8 (ii) 485/31 = 15.6

Math
#1 yes #3 yes #2 hmmm either 5(x-10)+x = 6x-50 or 5(x+10)+x = 6x+50

Geometry Probability
Do swimmers count among those who like sports? If not, then There are 17 swimmers, so P(boy if swimming) = 8/17 = .47 There are 27 sports, so P(girl if sports) = 7/27 = .26 Adjust the numbers if swimmers are counted among "sports" and so on. How did you get your ...

Algebra help pls
#1A "sum" means add. "product" multiply. #2C I have no idea how you came up with your answer. If you meant x/3 = 12 then multiply both sides by 3, since 3/3 = 1. Then you have x = 36 You did the multiplication, and then added another 3. Why? 39 is the ...

Algebra help pls
substitute the numbers for the variables. Does 5 = 3*2-1? Yes

physics
sorry - I misread your other post. The answer here is much simpler. 58 km/hr = 16.11 m/s distance = speed * time = 16.11 m/s * 0.742s = 11.95m

physics

physics
58 km/hr = 16.11 m/s Now use your usual formula for distance to get 5.98m

maths
sin2x+3cosx = 2 2sinxcosx+3cosx = 2 cosx(2sinx+3) = 2 2sinx+3 = secx cos3x = cos2xcosx-sin2xsinx = cos2xcosx-(2-3cosx)(2-3cosx)/(2cosx) = (2cos^2x-1)cosx-(2-3cosx)^2/(2cosx) I don't see where this is going. I fear that I am missing something here if you expect some simple ...

Differentiation
n is a constant. Usually variables are letters in the last part of the alphabet. So, if you mean x^(n+1) / (n+1) then using the power rule, the derivative is (n+1)x^(n+1-1) / (n+1) = x^n If you meant what you wrote, then the derivative is (nx^(n-1)+0)/(n+1) = n/(n+1) x^(n-1) ...

Math
"what number" is x, so .005x = 15 ...

Precalculus
For #3, (f?g)(x) = f(g) = g^2/(g^2-1) = (x+4)/(x+3) Since f(g) is not defined for g^2=1 x = -3 must be excluded g(x) is undefined when x < -4 x = 1,-1 are in the domain of f?g even though they are not in the domain of f.

C, because If you throw it up with a speed of 11 m/s, it will have that same speed downward when it returns to the top of the building.

Physics
It indicates that you have been using a measuring device with a .001 precision.

chemistry
191x + 193(1-x) = 192.23 x = .385 so, 38.5% Ir191 61.5% Ir193 or, since 192.23 is about 5/8 of the way from 191 to 193, 5/8 will be Ir193, or 62.5%. Fairly close ...

maths
LS: (1+tan^2)/(1+cot^2) * tan^2/tan^2 = tan^2(1+tan^2)/(tan^2+1) = tan^2 RS: (1-tan)^2/(1-cot)^2 = [(1-tan)/(1-cot)]^2 = [(1-tan)/(1-cot) * tan/tan]^2 = [tan(1-tan) / (tan-1)]^2 = [-tan]^2 = tan^2 LS = RS

Math
when dividing, subtract exponents. 7^8/7^2 = 7^(8-2) = 7^6 Think about it. What you have is 7*7*7*7*7*7*7*7 -----------------------        7*7 two of the factors cancel out, leaving 7^6 in the top.

Math
s = t+3 s = 2h t = h+2 so, let's solve for Hannah. t = h+2 t+3 = 2h, so t = 2h-3 That gives us h+2 = 2h-3 h = 5 So, Hannah is 5, Tim is 7, Steve is 10 (which is twice as old as Hannah)

Maths
another way to do it is to use the cot function. If the pole's height is h, then h cot67° + h cot 58° = 21 So, h = 21/(cot67°+cot58°) Then using h, the lengths of the wires are h csc 67° and h csc 58°

Math
Take a look at the Fundamental Theorem of Arithmetic.

yeah, what about it? "bisect" means it divides into two equal parts.

Geometry
JK+KL=JL 2x+1 + 8x = 81 x = 8

math
Add up the amounts of anti-freeze in the parts and the mixture. They must be the same. If x gallons of 100% anti-freeze are added, then .10*10 + 1.00x = .60(10+x)

Math
L1 has slope -5/8 L2 must have slope 8/5 So, the point-slope form of L2 is y-10 = 8/5 (x-10) y = 8/5 x - 6 m+b = 8/5 - 6 = -22/5

geometry
x: (7-1)/2 = 3 y: (3-3)/2 = 0 so, the midpoint is (3,0)

thank you

Robert borrowed \$750 from his parents to make some repairs on his car. He promised to repay the loan by giving his parents at least \$67 from his paycheck each week. Assuming Robert sticks to his promise, which of the following is not a possible scenario for the amount of debt ...

Reiny, there is no typo because what you put is what I would have said but based on the choices offered it's not that easy.

I believe #4 is correct. The original balance in Rudolph's account is -650. Using 76x-650, you are correct that the balance in the account after 5 weeks is -270. But, suppose he paid \$80 each week. Then the balance would be 5*80-650 = -250. But -250 >= -270. Actually, I...

Rudolph borrowed \$650 from his parents to make some repairs on his car. He promised to repay the loan by giving his parents at least \$76 from his paycheck each week. If x represents the number of weeks, which linear inequality represents the amount of debt Rudolph has ...

furth math
h + 2h+5 - 15 = 180 3h = 190 Hmmm. h must be an integer. I suspect a typo 63+131-15 = 179 64+133-15 = 182

College Algebra
There is no way to mix \$9/lb and \$6/lb nuts to make a mixture that costs \$127/lb. I assume you posted the other similar nuts question, since it has the same mistake. See the solution to that one for the method for this one.

Math
see your previous ice rink question for the method to solve.

College Algebra
See your previous similar question for the method of solution.

Math
the diagonal of the square is the same as the diameter of the circle. So, the diagonal is 0.35m L = 0.35/?2 m

Math @Reiny
Maybe oops. This question has been posted more than once, with differing numbers, just like the almonds/macadamia question and the walking/cycling questions.

Math
120-36 = 84 84 = 2*2*3*7 See what you can do with that.

College Algebra
g+y = 90 10g+6y = 900 ...

Math
1:30 to 2:15 = 3/4 hour 2:15 to 3:00 = 3/4 hour If his walking speed is w, then we have 3/4 * 3/2 w + 3/4 * w = 9.375 = 75/8 Now just solve for w...

Math
we want the *sum* to exceed 5000 ...

Math
Just use your formula for an arithmetic sequence n/2 (2*7+(n-1)*5 > 5000 n > 44 So, the 44th term is 7+43*5 = 222 check: 43/2 (14+42*5) = 4816 4816+222 = 5038

Math
what do segments have to do with boxes?

Math
Take a look at the differences. 2,3,9,23,48,87 1,6,14,25,39 5,8,11,14 3,3,3 The3rd difference is constant, so you need to find a cubic polynomial. I came up with 1/2 (n^3-n^2-2n+6) or 3 + (n-2)(n)(n+1)/2

Algebra
Since you have the vertex, use that for the equation. y = a(x-7)^2 - 2 Now just plug in your other point to find a.

Math
Hard to say, but I think you want P such that P*.08*15/2 = 1770

math
plug in your two points: 2/a + 8/b = 1 1/a + 5/b = 1 multiply the 2nd by 2 and you have 2/a + 8/b = 1 2/a + 10/b = 2 now subtract, and you have 2/b = 1 b = 2 use that to find that a=-2/3 x/(-2/3) + y/2 = 1 check the intercepts and you see that they are (-2/3,0) and (0,2) Now ...

College Algebra
distance = speed * time, so we have k = c+2 6k = 9(k-2) 3k = 18 k = 6 check: 6*6 = 4*9

College Algebra
add up the value of each part of the mix. Note that the \$95.75 is the total cost, not the cost per pound. 4.75x + 8(14-x) = 95.75

College Algebra
do this one the same way as the previous coin problem. Add up the values and use the information about how many coins there are.

College Algebra
24a+14=6(8a+3)-26a+4 24a+14 = 48a+18-26a+4 24a-48a+26a = 18+4-14 2a = 8 a = 4

College Algebra
just add up the coins and their values. 5n+10d = 80 n = d+5 Now just solve for n and d 10 nickels, 3 dimes

unt
25^x = 77 x log25 = log77 x = log77/log25 or, if you originally took logs base 25, x = log25</sub?77

Algebra
well, ?2 ? 1.414 so just multiply that by 4

Math
if there are 2 new frogs, then that means the population has tripled. After t years, there will be P(t) = 0.5 * 3^t kF

Math
2r-15

Marh
the volume of the sphere is 972? cm^3 since the area of the tank's cross-section is 144? cm^2, the height of the water column occupied by the sphere is 972? / 144? = 6.75 cm

Math
#1 "sum" means addition, not subtraction, so D: 7/(3+z) #2 correct #3 correct, if "7" was supposed to be "y" #4 correct

Spanish
yes

\math/
just multiply top and bottom 2/3 * 1/2 = (2*1)/(3*2) = 1/3 or, since half of 2 is 1, 1/2 of 2 boxes is 1 box 1/2 of \$2 is \$1 ... half of 2/3 is 1/3

Maths Mensuration
oh, man -- I missed it!

Maths Mensuration
well, it's 1/6 + 3/6 + 2/6 so what do you get?

Maths Mensuration
trace around a book

science
SnCl2 + 2HgCl2 --> Hg2Cl2 + SnCl4

Physics
For comparison, change all to m/s: 36 km/hr = 36000m/3600s = 10 m/s .8km/min = 800m/60s = 13.33 m/s A takes 100 seconds to reach Q. By that time, B has reached R C has passed S and is 33.33 m toward P So, BC = ?(1000^2 + 33.33^2) meters Since A and B are both moving at 10 m/s...

math
Draw two intersecting lines, using the straightedge. The lines form an angle. Label the vertex of the angle as point O. Set the compass to a convenient radius and using point O as the center, draw a circle. The circle will cut the sides of the angle. Label the two points of ...

Statistics
100

Math
I think you want to say that the width is w. So, the length is 3w-9. If so, then you have 2(w + 3w-9) = 342 Now just solve for w.

Math
-6 + 3*1 = -3

Math
Because f is continuous in the specified interval, the Intermediate Value Theorem applies. It can't get from 5 to -5 without assuming every value in between. In particular, zero.

Math
the only pairs of such integers are 1,34 2,17 -2,-17 -1,-34 so, what do you think?

Duh. what was I thinking?????

math 131 freshman college
4/5 is not 36/45. It is 32/45. 40 = 5*8, not 5*9

Math
Recall that |x| = x if x >= 0 |x| = -x if x < 0 So, |12| = 12 |-12| = 12 1A |-15| = 15, so -|-15| = -15 So, -|-15| < 15 3B recall that you can say 4 is 2 less than 6. That means 6-2 = 4 So, #2 is y-8 = 2 2C

Math
all are incorrect. Each is exactly backwards.

Math
that's a rate of 300mi/15gal = 20 mi/gal

Statistics
The mean now is 7, as is the median. Adding a number less than 6 will ensure that the new mean will be less than the new median (6+7)/2

Math
42 pupils in all, so 14/42 are girls

Algebra
If the 1st piece is x, then x + 2x + 2x+4 = 39 Now just find x and the rest follows.

Physics
(x+5)^2 = x^2+85 ...

Mensuration
The area of the border is (5*1.3) - (5-0.5)(1.3-0.5) = 2.9 m^2 so the cost is 2.9m^2 * (100cm/1m)^2 * rs1/10cm^2 = rs 2900

math
well, 3/4 + 6/8 = 3/2 the rest i guess is unchanged.

College Algebra
y is a function of x if you exclude x=0 from the domain.

Math
spent 1/3, so 2/3 left lost half of that, or 1/3 so, she has 1/3 left. That is \$10, so she started with \$30

Algebra
just divide all the exponents by 2: ?(x^20 y^2 z^10) = x^10 y z^5

Algebra
13?128 + 6?169 - 7?121 - 11?162 13?(64*2) + 6*13 - 7*11 - 11?(81*2) 13*8?2 + 78 - 77 - 11*9?2 104?2 + 1 - 99?2 1 + 5?2 don't just blindly copy and paste. There are no variables here, so that 2nd sentence is just noise.

Algebra 1
discount rate = change divided by original price: (3.80-3.67)/3.80 = 0.0342 = 3.4%

geometry
time = distance/speed, so (a) (1.2 + 0.5)/7.5 = 0.22666 hrs or 13.6 minutes (b) ?(1.2^2+0.5^2) = 1.3 miles (c) figure the time for (b) and then subtract from (a).

Science
A does not provide feedback. It just sets a temperature on the thermostat. Feedback means that a change causes another change. You want C. Once you do A, then C happens. Better review the topic of feedback.

math
I assume you mean sinx/(1+cosx) sinx(1-cosx) / (1+cosx)(1-cosx) sinx(1-cosx) / (1-cos^2x) sinx(1-cosx) / sin^2x (1-cosx)/sinx 1/sinx - cosx/sinx 1/sinx - cotx 1/sinx - 1/tanx

math
just compare the change in unit cost to the original unit cost... shovels: (70.38/2 - 172.50/5)/(172.50/5) = 0.02 salt: (26.04/4 - 6.20)/6.20 = 0.05 so, the shovels went up 2% and the salt went up 5%

math
I can't quite make out your equation, but it is easy to plug in x=45 sin2x = sin90 = 1 sin4x = sin180 = 0 and so on. If that still stumps you, show us how far you got, and try using some parentheses to make things clear, such as 1/(2-sin2x) and say sin^2x or sin^2(x) if ...

sounds good, as long as the 2nd pie is divided into 8 equal slices.

math
w * 2w * h = c So, h = c/(2w^2) So if the bottom costs \$1/m^2, the total cost is C(w,h) = w*2w + 3*w*2w + 3*2(wh + 2wh) = 7w^2 + 18wh C(w) = 7w^2 + 18w*c/(2w^2) = 7w^2 + 9c/w dC/dw = 14w - 9c/w^2 dC/dw=0 when (14w^3-9c) = 0 That is, when w = ?(9c/14) and so on to the length ...

Algebra
If their ages are younger sister: x Ulani: y elder sister: z then we have z = 2y+1 x = y-3 x+y+z = 26 (y-3) + y + (2y+1) = 26 4y-2 = 26 y = 7

Math
The "e" is the power of 10 (exponent) 1.8E-5 = 1.8 * 10^-5 = 0.000018 It's a hold-over from the old FORTRAN floating-point days. E for single-precision (7 decimal places), D for double-precision (16 decimal places)

Math
5^(-4y) = 3 -4y log5 = log3 -4y = log3/log5 y = -log3/(4log5) = 0.17

geometry
go look up the meaning of "context"