What is the missing length?

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?

The total number of dental clinics total for the last 12 months was recorded

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?