If the numbers that we are checking divisibility for are between 1-100, there are 3 numbers.
30, 60, and 90 are all divisible by both 3 and 10 because both 3 and 10 are factors of these 3 numbers.
Diameter of small pizza = diameter of large pizza divided by 2 = 9 inches
x = y divided by 2
x = 9 inches
We are told that f(1) = -1.5, and that f(n+1) = -2f(n).
Then: f(2) = -2f(1) = -2(-1.5) = +3 (answer)