algebra
posted by Anonymous .
A movie theater has 400 seats. Tickets at the theater cost $8 for students, $10 for adults, and $7 for senior citizens. On a night when all the seats were sold, the theater made $3,535 from ticket sales. If the number of adult tickets sold was 10 less than the number of student and senior tickets combined, how many senior tickets were sold?

If there are s students, a adults, and g geezers, then
s+a+g = 400
8s+10a+7g = 3535
a = s+g10
Now just solve for the numbers 
57

Reese read twice as many pages Saturday night than she read Sunday night. If she read a total of 78 pages over the weekend, how many pages did Reese read Sunday night?

36