Answer:
both cost $12
Step-by-step explanation:
Let's say the price of a senior citizen ticket is s dollars and the price of a child ticket is c dollars.
For, say, 7 senior citizen tickets, the cost would be s 7 times, or s * 7. Similarly, 6 child tickets would cost 6c. The total amount of (senior citizen ticket cost) + (child ticket cost) would equal the total sales.
Therefore,
first day:
7s + 6c = 156
second day:
7s + 3c = 120
7s + 6c = 156
7s + 3c = 120
we can solve this by solving for c in terms of s in one equation and plugging that into the other equation
7s + 6c = 156
subtract 7s from both sides to isolate the c and its coefficient
156 - 7s = 6c
divide both sides by 6 to isolate c
(156-7s)/6 = c
26-(7/6)s = c
plug that into the other equation
7s+3c = 120
7s + 3 (26-(7/6)s) = 120
7s + 78 - (21/6)s = 120
7s + 78 - (7/2)s = 120
(7/2)s + 78 = 120
subtract 78 from both sides to isolate s and its coefficient
(7/2)s = 42
multiply both sides by 2/7 to isolate s
12 = s
26 - (7/6)s = c
26 - 14 = c = 12
