Sarah left home at 10.10 a.m. and drove towards the countryside. 3 hours later, her uncle left their home and drove towards the same countryside at 88 km/h. When the uncle reached the countryside at 5.10 p.m., Sarah had another 2 km to travel. What was Sarah’s average speed? Express your answer in mixed number.
Time that the Sarah's uncle started driving = 1.10 p.m.
Duration that Sarah's uncle drove from 1.10 p.m. to 5.10 p.m. = 4 h

Distance that Sarah's uncle travelled
= 4 x 88
= 352 km

Distance that Sarah travelled by the time her uncle reached the city
= 352 - 2
= 350 km

Time that Sarah took to travel 350 km = 7 h

Sarah's average speed
= 350 ÷ 7
= 50 km/h

Answer(s): 50 km/h