Question

Y is directly proportional with x. Write an equation that shows the relationship if y=3 and x=12.

A. y=4x
B. 3y=12x
C. x=14y
D. y=14x

Answer 1

y =
`(1)/(4)` x

Explanation:

Given that y is directly proportional to x then the equation relating them is

y = kx ← k is the constant of proportion

To find k use the condition y = 3 when x = 12, then

3 = 12k ( divide both sides by 12 )

`(3)/(12)` =
`(1)/(4)` = k , thus

y =
`(1)/(4)` x ← equation of proportion