Victoria left home at 11.45 a.m. and drove towards the town. 3 hours later, her younger sister left their home and drove towards the same town at 100 km/h. When the younger sister reached the town at 7.45 p.m., Victoria had another 2 km to travel. What was Victoria’s average speed? Express your answer in mixed number.
Time that the Victoria's younger sister started driving = 2.45 p.m.
Duration that Victoria's younger sister drove from 2.45 p.m. to 7.45 p.m. = 5 h

Distance that Victoria's younger sister travelled
= 5 x 100
= 500 km

Distance that Victoria travelled by the time her younger sister reached the city
= 500 - 2
= 498 km

Time that Victoria took to travel 498 km = 8 h

Victoria's average speed
= 498 ÷ 8
= 62¹₄ km/h

Answer(s): 62¹₄ km/h