If y varies directly as x and y = 4 and x = 10, what does x equal when y = 7?

x = 17

Step-by-step explanation:

From the question: y α x

⇒ y = kx

y=4 and x = 10 implies

4 = 10k

k = 4/10

k = 2/5

substitute k = 2/5 into the equation

y = 2/5 x

When y = 7 , the equation becomes

7 =

35 = 2x

35/2 =x

Therefore : 17

x =

the answer is 31.27mph