Answer:
Since the area of your base is 15, we multiply 15 by 10 since 10 is the height and 15 is the area of the base to get 150, now we divide by 3 since we are multiplying 150 x 1/3 = 50.
Formula of triangular pyramid:
1/3 x BH
In this case 15 is your base and 10 is your height
15 x 10 x 1/3(basically just dividing by 3) = 50