# 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**

my bad. see your 2nd posting

**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.

**physics projectile - please help....**

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.

**Math. Please help!!**

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)

**Advanced Algebra**

thank you

**Advanced Algebra**

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 ...

**Advanced Algebra**

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.

**Advanced Algebra**

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...

**Advanced Algebra**

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?

**@Ouch! My bad!**

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 ...

**7th grade math**

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"