Emma left home at 11.35 a.m. and drove towards the suburb. 2 hours later, her older sister left their home and drove towards the same suburb at 88 km/h. When the older sister reached the suburb at 6.35 p.m., Emma had another 6 km to travel. What was Emma’s average speed? Express your answer in mixed number.
Time that the Emma's older sister started driving = 1.35 p.m.
Duration that Emma's older sister drove from 1.35 p.m. to 6.35 p.m. = 5 h

Distance that Emma's older sister travelled
= 5 x 88
= 440 km

Distance that Emma travelled by the time her older sister reached the city
= 440 - 6
= 434 km

Time that Emma took to travel 434 km = 7 h

Emma's average speed
= 434 ÷ 7
= 62 km/h

Answer(s): 62 km/h