Rachel left home at 11.10 a.m. and drove towards the seaside resort. 2 hours later, her grandfather left their home and drove towards the same seaside resort at 93 km/h. When the grandfather reached the seaside resort at 4.10 p.m., Rachel had another 3 km to travel. What was Rachel’s average speed? Express your answer in mixed number.
Time that the Rachel's grandfather started driving = 1.10 p.m.
Duration that Rachel's grandfather drove from 1.10 p.m. to 4.10 p.m. = 3 h

Distance that Rachel's grandfather travelled
= 3 x 93
= 279 km

Distance that Rachel travelled by the time her grandfather reached the city
= 279 - 3
= 276 km

Time that Rachel took to travel 276 km = 5 h

Rachel's average speed
= 276 ÷ 5
= 55¹₅ km/h

Answer(s): 55¹₅ km/h