MAth Problem NEED HELP?

Question

1) an inlet pipe can fill a tank in 90 mins.An outlet pipe can empty the tank in 135 mins.when both pipes are open how long does it take to fill the tank.

2)denise,Keith and sarah prepare the ballots for a school election in 2 hours.if,working alone,denise could prepare the ballots in 5 hours and keith could prepare them in 6 hours,how long will it take sarah to prepare the ballots alone.

Answer 1

You are in the wrong catagory.

Go to the MATH catagory.