Kathy went to the dancing class once every 2 days while Tina went to the same dancing class once every 9 days. They became friends after meeting each other at the dancing class on a Sunday. Which would be the next earliest day that they would meet each other again at the dancing class? Give the answer in number. (Eg Mon = 1; Tue = 2)
Multiples of 2: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24
Multiples of 9: 0, 9, 18
Lowest common multiple of 2 and 9: 18
Number of weeks in 18 days
= 18 ÷ 7
= 2 r 4
By looking at the remainder, we count 2 weeks and 4 days from Sunday is a (4) Thursday.
Answer(s): 4