Free GMAT Practice Question

Machines R and S each work at its own constant rate. Running at the same time, the two machines together finish a batch of parts in 12 hours. Running alone, machine S would need 10 more hours to finish the batch than machine R would need running alone.

In the table, select the number of hours Machine R alone would need and the number of hours Machine S alone would need to finish the batch. Make only two selections, one in each column.