প্রশ্ন:

A rectangular tank with dimensions 80 cm X 60 cm X 15 cm can be filled with tap A at the rate of 680 cm every 2 minutes and can be emptied with tap 1 at the rate of 140 cm every minute. It Jamal leaves both taps open at 2:30 pm, when will the tank be filed to 1 /3 prime its capacity?