The variable y is directly proportional to the variable x. If y = 10 when x = 6, what is the value of y when x = 15? A) 20.5 B) 25 C) 30 D) 35

The correct answer is B

Make a proportion and solve: 10/6=y/15

To determine the value of y when x = 15, we need to find the constant of proportionality between y and x first.

Since y is directly proportional to x, we can write the equation as y = kx, where k is the constant of proportionality.

To find the value of k, we can use the given information that when y = 10, x = 6. Substituting these values into the equation, we have 10 = k * 6.

Dividing both sides of the equation by 6, we get k = 10/6 = 5/3.

Now that we have the value of k, we can substitute it back into the equation to find y when x = 15. Using the equation y = kx, we have y = (5/3) * 15 = 25.

Therefore, the value of y when x = 15 is 25. The answer is B) 25.