Question

Variables x and y are in direct proportion, and y = 12.5 when x = 25. If x = 40, then y = ?

A) 20
B)28.5
C)52.5
D)65

Answer 1

(40/25)*12.5=20

Hope this helps :)

Answer 2

Option A.
`y=20`

Explanation:

we know that

A relationship between two variables, x, and y, represent a direct proportion if it can be expressed in the form
`y/x=k` or
`y=kx`

so

we have

For
`x=25,y=12.5`

Find the value of k

`k=y/x`

substitute the values

`k=12.5/25=0.5`

The equation of the linear direct variation is equal to

`y=0.5x`

For
`x=40,y=?`

substitute the value of x in the equation to find the value of y

`y=0.5(40)=20`