time = distance/speed
a) Your driving time for the first 130 km was
.. time = distance/speed
.. time = (130 km)/(95 km/h) = 26/19 h
Your remaining drive time is
.. (3 20/60 h) -(26/19 h) = 112/57 h . . . . (about 1 h, 57 minutes, 53.7 seconds)
The distance you travel in that remaining time is
.. distance = speed*time
.. distance = (65 km/h)*(112/57 h) = 127 41/57 km
The total distance you have driven is (130 km) +(127 41/57 km) = 257 41/57 km
.. about 257.72 km
b) Your average speed can be computed by
.. speed = distance/time
.. speed = (257 41/57 km)/(3 1/3 h)
.. speed = 77 6/19 km/h
Your average speed is about 77.32 km/h
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My calculator works well with fractions, so I mostly left the numbers "exact."
