Esther left home at 11.10 a.m. and drove towards the province. 2 hours later, her grandfather left their home and drove towards the same province at 93 km/h. When the grandfather reached the province at 4.10 p.m., Esther had another 6 km to travel. What was Esther’s average speed? Express your answer in mixed number.
Time that the Esther's grandfather started driving = 1.10 p.m.
Duration that Esther's grandfather drove from 1.10 p.m. to 4.10 p.m. = 3 h

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

Distance that Esther travelled by the time her grandfather reached the city
= 279 - 6
= 273 km

Time that Esther took to travel 273 km = 5 h

Esther's average speed
= 273 ÷ 5
= 54³₅ km/h

Answer(s): 54³₅ km/h