Answer: 8 pizzas.
Step-by-step explanation:If she is ordering 4 pizzas for 15 people then that simply means that the fraction is 4/15, 15*2 is 30, so that means that our next fraction (Equivalent fraction) will be like this 4/15 = -/30. What ever. Happens to the numerator must happen to the denominator and vice versa. So 4*2 is 8. So the answer is 8.