Question

Ronald and Tim did their laundry today. Ronald does laundry every 6 days and Tom does laundry every 9 days. How many days will it be until Ronald and Tim do their laundry on the same day again?

Answer 1

Least common multiple question

Ronald: count by 6's
 6, 12, 18, 24, 30, 36, 42, 48, 54 ....

Tim: count by 9's
9, 18, 27, 36, 45, 54,

every 18 days they do their laundry together