A) time = distance/speed
For the first half of the trip, the time used was
.. (1 mi)/(12 mi/h) = (1/12) h = 5 minutes
Then the last half of the trip took 10 minutes, 1/6 hour.
.. speed = distance/time
.. = (1 mi)/(1/6 h) = 6 mi/h
The speed for the last half of the trip was 6 mph.
b) The average speed was
.. (2 mi)/(1/4 h) = 8 mi/h
Ling's average speed was 8 mph.
Subtract 9x from 23x yields 14x. This was done by subtracting algebraically the variables.
330/3= 110
550/110=5
Answer is 5 books
