Question

If x and y vary directly, and x = 10 when y = 3, what will be the value of x when y = 9?

Answer 1

from x = 10 and y = 3
we have:

3 = k*10

so
k = 3/10

and we have:
y = (3/10)x

evaluating at y = 9:
9 = (3/10)x
x = (10/3)*9
x = 30

Answer 2

go hayhay

Answer 3

Bam!!

Answer 4

thank you!!