Question

Given that y varies directly with x and that y = 60 when x = 20, find y when x = 12.

Answer 1

1.y varies directly with x

2.substitute the value of x and y in the equation below

y=kx

where k is the constant term

60=20k

k=60\20

k=30

:y=30x.....is the law

To find y when x is 12

You reinstate the law which is y=30x

Then substitutes the value of x to determine y

y=30*12

y=36.