# algebra

y varies directly with x. When y = 20, x = 50. Find x when y = 36.

1. 👍
2. 👎
3. 👁
1. y varies directly with x ----> y = kx , where k is a constant

20 = k(50
k = 2/5

y = (2/5)x
when y = 36
36 = (2/5)x
2x = 180
x = 90

or ... use a proportion

x/50 = 36/20
x = 50(36)/20 = 90

1. 👍
2. 👎

1. 👍
2. 👎

## Similar Questions

1. ### math

p varies directly as q and the square of r and inversely as s write the equation of the relation find k if p=40 q=5 r=4 s=6 find p when q=8 r=6 and s=9 find s when p=10 q=5 r=2

2. ### 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

If c varies directly as the square root of d, and c = 14 when d = 64, find c when d = 324.

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. ### Pre-Algebra

If y varies directly with x, find the constant of variation with x = 4 and y = -24 If y varies inversely with x, find the constant of variation with x=5 and y = 10 If y varies directly with x, and y = 35 when x = 5 , find x when y

2. ### math

P varies directly as the square root of q. P=8 when q =25 find p when q = 100

3. ### Mathematics

M varies directly as n and inversely as p. if M=3, when n=2,and p=1, find M in terms of n and p

4. ### Algebra II

if y varies directly as x, if y=80 when x=32, find x if y=100

1. ### algebra

I do not know where to start with this one. Suppose p varies directly as the square of z and inversely as r. If p = 32/5 when z = 4 and r = 10, find p when z = 3 and r = 36.

2. ### Math

Y varies directly as the square of x and y=96 when x=4 find the value of y when x=5

3. ### Math help

9). Hooke’s Law. The distance d when a spring is stretched by a hanging object varies directly as the weight w of the object. If the distance is 29 cm when the weight is 4 kg what is the distance when the weight is 9 kg? 10).

4. ### algebra 1

Suppose y varies directly as x and that y = 21 when x = 3. Find the value of y when x = 5. Would I be wrong if I said y = 35? In using y = kx with the 21 and the 3 k = 7. So if y = 35 and x = 5 then k = 7. Am I correct or am I way