Question

Suppose y varies directly with x. If y = 3 when x = 2, find y when x = 3.

A *9/2
B *2/3
C *3/2
D *2/9​

Answer 1

A

Explanation:

given y varies directly with x then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = 3 when x = 2 , then

3 = 2x ( divide both sides by 2 )

`(3)/(2)` = k

y =
`(3)/(2)` x ← equation of variation

When x = 3 , then

y =
`(3)/(2)` × 3 =
`(9)/(2)` → A

Answer 2

9/2

Explanation:

Direct variation is

y = kx where k is the constant of variation

Substitute into the equation to find k

y=3 and x=2

3 = k*2

Solve for k

3/2 = k

y = 3/2 x

We know x =3

y = 3/2 * 3

y = 9/2