Question

X varies directly as y. If x is 9 when y is 4, find x when-y is 8.

a) Write the variation.
b) Find x when y is 8.
a) How are these two variables related?
i oo
OD. x=ky
b) The quantity indicated is

Answer 1

see explanation

Explanation:

Given x varies directly as y then the equation relating them is

x = ky ← k is the constant of variation

To find k use the condition x = 9 when y = 4

k =
`(x)/(y)` =
`(9)/(4)` = 2.25

x = 2.25y ← equation of variation

When y = 8, then

x = 2.25 × 8 = 18