Number of Playbills = P
First he arranged them all into four piles, but there was one Playbill left over. (n per pile)
P = 4n + 1
So then he tried five piles, but this time there were three Playbills left over. (m per pile)
P = 5m + 3
So then he tried seven piles, but there were 4 Playbills left over. (j per pile)
P = 7j + 4
4n + 1 = 5m + 3 ==> 4n = 5m + 3 -1 = 5m + 2
4n = 5m + 2
n = (5m + 2)/4
5m + 3 = 7j + 4
7j = 5m + 3 - 4 = 5m -1
j = (5m -1)/7
Making a table for different values of n, m and j that result in integers and keep P less than 100:
n = 13
m = 10
j = 7
P = 4(13) + 1 = 53
P = 5(10) + 3 = 53
P = 7(7) + 4 = 53
Answer:
Lin has 53 Playbills