Suppose that y varies directly with x and y = 10 when x = 20. What is y when x = 15?

Given that,

y varies directly with x and y = 10 when x = 20.

To find,

The value of y when x = 15.

Solution,

Put x = 20 and y = 10

Put k = 1/2 and x = 15 to find the value of y.

So, the value of y is 7.5

answer: c

because if you look at the chart you can see a pattern and compare it to the question he simplify out your

but i think the formula is f(x)=6x