Answer:
180 days
Step-by-step explanation:
To solve for the least number of days all three will again be report to the principal, find the lowest common multiples of all three of them
Rachel will report to the principal every 9 days, Jessica every 12 days, and Richard every 15 days
Rachel (every 9 days) = 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108, 117, 126, 135, 144, 153, 162, 171, 180
Jessica (every 12 days) = 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180
Richard (every 15 days) = 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180
The lowest common multiples of 9 days, 12 days, 15 days is 180 days
Therefore, the least number of days all three will report again to the principal is 180 days
