Human: Tom swims for 2 hours at a speed of 2 miles per hour.  He then runs for half the time at 4 times the speed.  How many miles did he cover? Assistant:
He swam 2*2=4 miles
He ran for 2/2=1 hour
His running speed was 2*4=8 mph
So he ran 8*1=8 miles
So his total distance was 8+4=12 miles