Question

Suppose y varies directly as x, and y = 10 when x = 6. What is the value of x when y = 20?

Answer 1

direct variation is y=kx so we have a y and x. we need to find k so substitute y and x
10=6k
k=10/6 or 5/3
now we substitute k into the equation
y=5/3x we can now substitue y
20=5/3x multiply by 3/5 or divide by 5/3
x=12