Zoe left home at 10.40 a.m. and drove towards the suburb. 3 hours later, her older brother left their home and drove towards the same suburb at 92 km/h. When the older brother reached the suburb at 6.40 p.m., Zoe had another 2 km to travel. What was Zoe’s average speed? Express your answer in mixed number.
Time that the Zoe's older brother started driving = 1.40 p.m.
Duration that Zoe's older brother drove from 1.40 p.m. to 6.40 p.m. = 5 h

Distance that Zoe's older brother travelled
= 5 x 92
= 460 km

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

Time that Zoe took to travel 458 km = 8 h

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

Answer(s): 57¹₄ km/h