Question

Suppose that c varies jointly with d and the square of g, and c = 30 when d = 15 and g = 2.

Find d when c = 6 and g = 8. Write the equation of the variation.​

Answer 1

`d = (3)/(16)`

Explanation:

c varies jointly with d and the square of g

`c\propto dg^2`

`c=kdg^2`

where, k is constant of proportionality.

Put the given value c = 30 when d = 15 and g = 2 and find out k

`30=k\cdot 15\cdot 2^2`

`k=(1)/(2)`

`c=(1)/(2)kg^2`

If c = 6 and g = 8 then d = ?

`6=(1)/(2)\cdot d\cdot 8^2`

`d=(6\cdot 2)/(8^2)`

`d=(3)/(16)`

Hence, The value of d is
`(3)/(16)`