Nicole left home at 11.50 a.m. and drove towards the suburb. 3 hours later, her younger sister left their home and drove towards the same suburb at 88 km/h. When the younger sister reached the suburb at 7.50 p.m., Nicole had another 2 km to travel. What was Nicole’s average speed? Express your answer in mixed number.
Time that the Nicole's younger sister started driving = 2.50 p.m.
Duration that Nicole's younger sister drove from 2.50 p.m. to 7.50 p.m. = 5 h

Distance that Nicole's younger sister travelled
= 5 x 88
= 440 km

Distance that Nicole travelled by the time her younger sister reached the city
= 440 - 2
= 438 km

Time that Nicole took to travel 438 km = 8 h

Nicole's average speed
= 438 ÷ 8
= 54³₄ km/h

Answer(s): 54³₄ km/h