Question

Suppose that r varies directly with s and inversely with t, and r=2 when s=3 and t=12. What is the value of r when s=5 and t=4?

I already know the answer but I'd like to know how to find it.

Answer 1

R would equal to 10:

C. R=10

Also:

1. B

2.A(y=16/x)

3.C(nc=100)

4.C(10)

5.C(2,224 dolls)

Answer 2

r = ks / t
2 = 3k / 12
k = (2 x 12) / 3 = 24 / 3 = 8

Thus, r = 8s / t
r = (8 x 5) / 4 = 40 / 4 = 10
r = 10