Answer:
Speed = distance/time
we calculate the average speed of each race
1st race in miles/min
speed = 1.2/2 = 0.6
2nd race e, miles/min
speed = 2.3/5 = 0.46
we calculate the average speed over the 2 races
distance: 1.2+2.3=3.5 miles
time: 0.6+0.46= 1.06
average speed: 3.5/1.06=3.3miles/min = 60mph