Question

Suppose y varies directly with x. If y = 6 when x = -2, find x when y = 15.

a. ⅕
b. 5
c. -5
d. -⅕

Answer 1

D because u going to take y6 and y 15 multiples the number it equal to y90 and take x-2 divide into 90

Answer 2

C. -5

Explanation:

Since, y varies directly with x,

⇒ y ∝ x

⇒ y = kx -----(1)

Where k is the constant of proportionality,

Given,

y = 6 when x = - 2,

From equation (1),

`6=k(-2)`

`\implies k = (6)/(-2)=-3`

Again from equation (1),

y = - 3x

If y = 15,

`15 = -3x`

`\implies x = -(15)/(3)=-5`

Hence, option C is correct.