Question

Suppose that y varies directly with x, and y = 4 when x = 10.

1. Write a direct variation question that relates x and y.

2. Find y when x = 15.

Answer 1

Answer: If x=15 what is y? Y=26

Answer 2

One possible direct variation question that relates x and y is:

"If y varies directly with x, what is the value of y when x = k?"

Here, k represents any constant value of x that we are interested in finding the corresponding value of y for.

To find y when x = 15, we can use the information given that y varies directly with x. This means that there is a constant of proportionality, k, such that:

y = kx

We can find k by using the initial condition that y = 4 when x = 10:

4 = k(10)

Solving for k gives:

k = 4/10 = 0.4

Now that we have k, we can use the direct variation equation to find y when x = 15:

y = 0.4(15) = 6

Therefore, when x = 15, y = 6.