Lucy left home at 11.20 a.m. and drove towards the city. 2 hours later, her older sister left their home and drove towards the same city at 98 km/h. When the older sister reached the city at 4.20 p.m., Lucy had another 4 km to travel. What was Lucy’s average speed? Express your answer in mixed number.
Time that the Lucy's older sister started driving = 1.20 p.m.
Duration that Lucy's older sister drove from 1.20 p.m. to 4.20 p.m. = 3 h

Distance that Lucy's older sister travelled
= 3 x 98
= 294 km

Distance that Lucy travelled by the time her older sister reached the city
= 294 - 4
= 290 km

Time that Lucy took to travel 290 km = 5 h

Lucy's average speed
= 290 ÷ 5
= 58 km/h

Answer(s): 58 km/h