Question

At an aquarium, a tour of shark tanks begins every 45 minutes. The dolphin show begins every 30 minutes. If the shark tour and dolphin show both begin at 9 A.M., at what time will they start at the same time again? Explain your answer.

Answer 1

Answer: 10:30 A.M.

Explanation:

both 45 and 30 have common multiples of 90. since we're measuring the time in minutes this means they both will be starting 90 minutes after 9. there are 60 minutes in an hour. so if you add that hour and subtract it from the 90 minutes, that brings you to 10 A.M. with 30 more minutes. add the other 30 minutes and it brings you to 10:30 A.M. so therefore 90 minutes after 9 is 10:30 A.M.