Question

If a varies jointly as b and c,

and a=6 when b=2 and a=3.
Find the variation constant and
the equation of variation.​

Answer 1

Given:

a varies jointly as b and c.

a=6 when b=2 and a=3.

To find:

The variation constant and the equation of variation.

Solution:

a varies jointly as b and c.

`a\propto bc`

`a=kbc` ...(i)

Where, k is the constant of proportionality.

a=6 when b=2 and a=3.

`6=k(2)(3)`

`6=6k`

`(6)/(6)=k`

`1=k`

The value of k is 1.

Putting k=1 in (i), we get

`w=1xy`

`w=xy`

Therefore, the variation constant is 1 and the equation of variation is
`w=xy`.