Question 13
Two pipes A and B can fill a cistern in $37\frac12$ minutes and 45 minutes respectively. Both pipes are opened. For how many minutes is pipe B turned on so that the cistern will be filled in just half an hour?
Operating convention used in the source solution: A stays on throughout all 30 minutes; the cistern starts empty and both rates are constant.
Operating convention used in the source solution: A stays on throughout all 30 minutes; the cistern starts empty and both rates are constant.