Question

The director of a marching band asks the band members to line up in rows of four, but one is left over. Then she tries to line them up in rows of six, but three are left over. Finally, she tries to line them up in rows of seven, but four are left over. The band has fewer than $100$ members. How many members are there?

Answer 1

I got 81 members. 4 x 20 = 80 81-80=1
6 x 13= 78 81-78= 3
7 x 11= 77 81-77= 4