A 600L water tank is full to the top. One day, it started leaking at a rate of 15L per hour, when it was half way, water is added at a rate of 20L per hour, how long will it take for the tank to be full again?

Answer 1

time to drain halfway: 300/15 = 20 hr
time to fill back up: 300/5 = 60 hr

Answer 2

Thanks for your response, but according to my teacher it's 80 hours. Could you please see why that is the answer.

Answer 3

well, 20+60=80
I guess she started counting when the tank started to leak...