1. Questions

Algebra 2 Honors

I have a question on my math homework.
The problem is: Suppose r varies jointly as s and t. If s = 20 when r = 140 and t = -5, find s when r = 7 and t = 2.5.

I used r = kst. I plug in and get 140 = k(20)(5). I then multiply and get 140 = k(-100). I then divide each side by -100 and get k = -7/5. I replug and get an equation of 7 = -7/5(2.5)s. I multiple this and get 7 = -3.5s. I divide each side by -3.5 and get s = -2.

My final answer is s = -2, I just want to know if this is correct.

  1. 👍
  2. 👎
  3. 👁
Ronald

  1. you can get that without worrying about k.

    since r = kst, r/st = k and is constant. So, you need s in

    140/(-5*20) = 7/(2.5s)
    s = -2
    as you calculated

    1. 👍
    2. 👎
    Steve

Respond to this Question

First Name

Your Response

Similar Questions

  1. Algebra worksheet

    Hello. My algebra teacher gave me this worksheet last week and everyone had to bring it yesterday and I haven't done it yet. Can someone please help me. He said Friday is the last day or he's going to take away some points. I've

  2. HELP!!! Math

    If a varies jointly as b and the square root of c, and a = 21 when b = 5 and c = 36, find a when b = 9 and c = 225.

  3. HELP!!! Math

    If y varies jointly as x and z, and y = 33 when x = 9 and z = 12, find y and x = 16 and = 22.

  4. variation

    Can you please check my answers? Thanxs! Write an equation that expresses the relationship. Use k as the constant of variation. 20. f varies jointly as b and the square of c. -I got: f=kbc^2 22. r varies jointly as the square of s

  1. math

    if Y varies jointly as X and the square of Z, and if Y=24 when X=2 and Z=6, find Y when X=10 and Z=9

  2. Algebra

    Find an equation of variation in which y varies jointly as x and z, and y=4 when x=4 and z=1. Simplify

  3. Interediate algebra

    if f varies jointly as q^2 and h, and if f = 72 when q = 3 and h = 4, find h when f = 48 and q = 2

  4. Math

    R varies jointly as S and the square of T. If R is 32.4 when S=0.2 and T=9, find R when S=0.5 and T=5. I believe the answer is R=25, could someone check this for me?

  1. algebra

    z varies jointly with y and the square of x. If x=-2 when y=7 and z=-84,find x when z=-96 and y=2 I just need help figuring out what equation to use.

  2. math

    1)The area A of a triangle varies jointly as the lengths of its base b and height h. If A is 75 when b=15 and h=10,find A when b=8 and h=6 2)Determine the equation of any vertical asymtotes of the graph of f(x)=2x+3/x^2+2x-3 1)

  3. Algebra

    If f varies jointly as q2 and h, and f=24 when q=2 and h=2, find f when q=3 and h=5

  4. Algebra

    Find a mathematical model representing the statement. (Determine the constant of proportionality.) v varies jointly as p and q and inversely as the square of s. (v = 2.1 when p = 4.2, q = 5.4 and s = 2.4.) v =

You can view more similar questions or ask a new question.