VARIATION 2

x is directly proportional to y. x=36 while y=4. Find y when x is 720.

Solution

x ⍺ y

x = ky

36 = k x 4

36 = 4k    [dividing by 4 both sides]

4      4

k = 9

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

k = 9, y= ? x = 720.

x = ky

720 = 9 x y

720 = 9y

9       9

y = 80.

TRY THIS…………….

x is directly proportional to y. x=40 while y=5. Find y when x is 496.