chetan2u wrote:
A certain theater has 500 seats. Some are on the main floor and sell for $50 each; some are in the first balcony and sell for $45 each; and the rest are in the second balcony and sell for $35 each. When all of the seats are sold for a performance, the gross revenue for that performance is $20,900. Of the three seating areas, the second balcony has the most seats.
Select for
First balcony a number of seats in this theater’s first balcony and select for
Second balcony a number of seats in this theater’s second balcony such that the selections are jointly consistent with the information provided. Make only two selections, one in each column.
Let the number of seats on the main floor, first bacony and second balcony be m,f and s respectively.
m+f+s = 500
50m+45f+35s = 20,900......50(500-f-s)+45f+35s = 20900.......25000-5f-15s=20900.......5f+15s=4100.....f+3s=820
f cannot be a multiple of 3, otherwise f+3s would also be a multiple of 3.
so f can be
100: 100+3s = 820......3s=720 or s=240...Not in options
190: 190+3s = 820......3s=630 or s=210....Yes, possible
250: 250+3s = 820......3s=570 or s=190.....Yes, possible but this will make f>s
Solution: f = 190 and s = 210