What is the greatest commen factor of 65 and 39

Pls! does anybody know a shortcut for answering these types of questions in the future?

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?

How long does it take natsumi to clean up after she is done? table: .area time30. 245. 2.7560. 3.5