Question

D varies as R and S, and inversely as t. D=12, R=3, S=20, and t=5, find D when R=15, S=4 and t=8.

Answer 1

d = 7.5

Explanation:

Given that,

D varies as R and S, and inversely as t. It can be written as :

`D=(kRS)/(t)`

Where

k is constant of proportionality

Put D=12, R=3, S=20, and t=5 to find k. So,

`k=(Dt)/(RS)\\\\k=(12* 5)/(3* 20)\\\\k=1`

Now put R=15, S=4, k=1 and t=8 to find D. So,

`D=(1* 15* 4)/(8)\\\\D=7.5`

Hence, the value of d is equal to 7.5.