Answer :
average speed = total distance / total time ........(i)
here total distance = 100+30 = 130 miles
time = distance / speed
time for step 1 = t1 = 100/60 = 1.6667 hours
time for step 2 = t2 = 30/40 = 0.75 hours
so total time = t = t1+t2 =2.416667hours
put values of distance and time in equation (i) we get
average speed = 130 / 2.416667 = 53.79 = 53.8 miles per hour
here total distance = 100+30 = 130 miles
time = distance / speed
time for step 1 = t1 = 100/60 = 1.6667 hours
time for step 2 = t2 = 30/40 = 0.75 hours
so total time = t = t1+t2 =2.416667hours
put values of distance and time in equation (i) we get
average speed = 130 / 2.416667 = 53.79 = 53.8 miles per hour