Shannon left home at 11.35 a.m. and drove towards the countryside. 3 hours later, her uncle left their home and drove towards the same countryside at 100 km/h. When the uncle reached the countryside at 7.35 p.m., Shannon had another 4 km to travel. What was Shannon’s average speed? Express your answer in mixed number.
Time that the Shannon's uncle started driving = 2.35 p.m.
Duration that Shannon's uncle drove from 2.35 p.m. to 7.35 p.m. = 5 h

Distance that Shannon's uncle travelled
= 5 x 100
= 500 km

Distance that Shannon travelled by the time her uncle reached the city
= 500 - 4
= 496 km

Time that Shannon took to travel 496 km = 8 h

Shannon's average speed
= 496 ÷ 8
= 62 km/h

Answer(s): 62 km/h