Shannon left home at 11.55 a.m. and drove towards the province. 3 hours later, her younger sister left their home and drove towards the same province at 92 km/h. When the younger sister reached the province at 6.55 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 younger sister started driving = 2.55 p.m.
Duration that Shannon's younger sister drove from 2.55 p.m. to 6.55 p.m. = 4 h

Distance that Shannon's younger sister travelled
= 4 x 92
= 368 km

Distance that Shannon travelled by the time her younger sister reached the city
= 368 - 4
= 364 km

Time that Shannon took to travel 364 km = 7 h

Shannon's average speed
= 364 ÷ 7
= 52 km/h

Answer(s): 52 km/h