Answer:
Consider the following cases
Case 1: In n first gear,  an automobile's engine runs about three times as fast as the drive shaft.
So, if Speed of Engine = 1,850 r.p.m
Then Speed of Drive Shaft   r.p.m
 r.p.m
Case 2 : In second gear, the engine does not have to run as fast; usually it runs about 1.6 times faster than the drive shaft.
  So, if Speed of Engine = 1,850 r.p.m
Then Speed of Drive Shaft   r.p.m
 r.p.m
Case 3:  Finally, in third, or high gear, the engine runs at the same speed as the drive shaft.
 So, if Speed of Engine = 1,850 r.p.m
Then Speed of Drive Shaft is also equal to 1,850 r.p.m