ZWork applications

Question

How to solve , a bank can process and prepare statements in 30hr. A new computer can do the job in 20 hrs. If the bank uses both computers together, how long will it take to process the statements

Answer 1

To make it simpler, imagine that there are 60 statements.

The old computer can manage 60 statements in 30 hours, which is 60/30=2 statements in an hour.

The new computer can manage 60 statements in 20 hours, which is 60/20=3 statements in an hour.

Together they can manage 2+3=5 statements in an hour. So it would take 60/5=12 hours.