Jaslyn left home at 11.55 a.m. and drove towards the countryside. 3 hours later, her older sister left their home and drove towards the same countryside at 92 km/h. When the older sister reached the countryside at 7.55 p.m., Jaslyn had another 2 km to travel. What was Jaslyn’s average speed? Express your answer in mixed number.
Time that the Jaslyn's older sister started driving = 2.55 p.m.
Duration that Jaslyn's older sister drove from 2.55 p.m. to 7.55 p.m. = 5 h

Distance that Jaslyn's older sister travelled
= 5 x 92
= 460 km

Distance that Jaslyn travelled by the time her older sister reached the city
= 460 - 2
= 458 km

Time that Jaslyn took to travel 458 km = 8 h

Jaslyn's average speed
= 458 ÷ 8
= 57¹₄ km/h

Answer(s): 57¹₄ km/h