Elyse left home at 11.20 a.m. and drove towards the city. 3 hours later, her grandmother left their home and drove towards the same city at 88 km/h. When the grandmother reached the city at 7.20 p.m., Elyse had another 6 km to travel. What was Elyse’s average speed? Express your answer in mixed number.
Time that the Elyse's grandmother started driving = 2.20 p.m.
Duration that Elyse's grandmother drove from 2.20 p.m. to 7.20 p.m. = 5 h

Distance that Elyse's grandmother travelled
= 5 x 88
= 440 km

Distance that Elyse travelled by the time her grandmother reached the city
= 440 - 6
= 434 km

Time that Elyse took to travel 434 km = 8 h

Elyse's average speed
= 434 ÷ 8
= 54¹₄ km/h

Answer(s): 54¹₄ km/h