Amos counts out loud by 8 beginning with 0. Sarah counts out loud by 7 also beginning with 0. Between 2000 and 3000 inclusive, how many of the numbers do both Sarah and Amos say out loud?
LCM of 7 , 8 = 56
The first number that they say together = 2016
The last number that the say together = 2968
Number of integers that both say out loud = [ 2968 - 2016 ] / 56 + 1 = 952/56 + 1 = 17 + 1 = 18