Lisa can shovel snow from her driveway in 50 minutes Jim can

Lisa can shovel snow from her driveway in

50

minutes.

Jim

can do the same job in

45

minutes. How long would it take

Lisa

and

Jim

to shovel the driveway if they worked together?

Solution

Lisa can shovel snow from her driveway in 50 minutes.. Therefore, Lisa can clear 1/50 of her driveway in 1 minute.

Jim can shovel snow from the same driveway in 45 minutes.. Therefore, Jim can clear 1/45 of the driveway in 1 minute. Thus, Lisa and Jim, together, can can clear (1/50 +1/45) = ( 9+10)/450 = 19/450 of the driveway in 1 minute. Hence, if Lisa and Jim shovel snow from the driveway together, they can complete the job in 450/19 minutes = 23 .68421 minutes or, 23 minutes, 41 seconds (approximately)