If we want to know the total revenue that the theater received, we need to know:
(# of full-price tickets)x(full-ticket price) + (# of reduced-price tickets)x(reduced-ticket price)
I'll assign the following variables for clarity:
number of full-price tickets = F
price of each full-ticket = f
number of reduced-price tickets = R
price of each reduced-ticket = r
Revenue = (F)(f) + (R)(r)
In order to answer the question, we'd need values for each of these variables: F, f, R, and r.
We're given the total # of tickets, so we know that F + R = 400. If we knew a proportion between F and R, we could infer the values. We would still need actual values for f and r.
Target question: what are the values of F, f, R, and r?
(1) The number of tickets sold at the full price was 1/4 of the total number of tickets sold.
This allows us to infer that F = 100 and R = 300. We still don't know the prices of each ticket, so we don't know total revenue. Insufficient.
(2) The full price of a ticket was $25.
With this statement alone, we know that f = 25, but we do not know how many of each ticket was sold, or the price of reduced tickets. Insufficient.
(1) & (2) together
We know that F = 100, f = 25, and R = 300. However, we still don't know anything about the price of reduced tickets, so we don't know the total revenue. Insufficient.
The answer is E.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education