Question

Y varies directly with x, and y=24 when x=-15. what is x when y=16? a) 10 b) -22.5 c) -10 d) -25.6

Answer 1

Answer:

c

Step-by-step explanation:

Given that y varies directly with x then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = 24 when x = - 15, then

24 = - 15k ( divide both sides by - 15 )

k = $\frac{24}{-15}$ = - $\frac{8}{5}$ = - 1.6 , thus

y = - 1.6x ← equation of variation

When y = 16, then

16 = - 1.6x ( divide both sides by - 1.6 )

x = - 10 → c