Emily left home at 10.35 a.m. and drove towards the countryside. 3 hours later, her grandfather left their home and drove towards the same countryside at 92 km/h. When the grandfather reached the countryside at 6.35 p.m., Emily had another 6 km to travel. What was Emily’s average speed? Express your answer in mixed number.
Time that the Emily's grandfather started driving = 1.35 p.m.
Duration that Emily's grandfather drove from 1.35 p.m. to 6.35 p.m. = 5 h

Distance that Emily's grandfather travelled
= 5 x 92
= 460 km

Distance that Emily travelled by the time her grandfather reached the city
= 460 - 6
= 454 km

Time that Emily took to travel 454 km = 8 h

Emily's average speed
= 454 ÷ 8
= 56³₄ km/h

Answer(s): 56³₄ km/h