Abi went to the aerobics class once every 5 days while Gillian went to the same aerobics class once every 2 days. They became friends after meeting each other at the aerobics class on a Monday. Which would be the next earliest day that they would meet each other again at the aerobics class? Give the answer in number. (Eg Mon = 1; Tue = 2)
Multiples of 5: 0, 5, 10, 15, 20
Multiples of 2: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24
Lowest common multiple of 5 and 2: 10
Number of weeks in 10 days
= 10 ÷ 7
= 1 r 3
By looking at the remainder, we count 1 week and 3 days from Monday is a (4) Thursday.
Answer(s): 4