Question

Two pipes A and B can fill a cistern in 20 minutes and 30 minutes
respectively. If these pipes are turned on alternately for 1 minute each
how long will it take to the cistern to fill?​

Answer 1

Answer:

12 minutes i think

Step-by-step explanation:

because 1/20 + 1/30 = 5/60 or 1/12

1/12 = 12 minutes