Problem: one pump drains one - half of a pond in 2 hours , and then a second pump starts draining the pond . the two pumps working together finish emptying the pond in one - half hour . how long would it take the second pump to drain the pond if it had to do the job alone ? 
Options: a ) 1.3 hour , b ) 1.2 hour , c ) 3 hours , d ) 5 hours , e ) 6 hours
a