Zoe left home at 11.15 a.m. and drove towards the countryside. 2 hours later, her older brother left their home and drove towards the same countryside at 93 km/h. When the older brother reached the countryside at 4.15 p.m., Zoe had another 5 km to travel. What was Zoe’s average speed? Express your answer in mixed number.
Time that the Zoe's older brother started driving = 1.15 p.m.
Duration that Zoe's older brother drove from 1.15 p.m. to 4.15 p.m. = 3 h

Distance that Zoe's older brother travelled
= 3 x 93
= 279 km

Distance that Zoe travelled by the time her older brother reached the city
= 279 - 5
= 274 km

Time that Zoe took to travel 274 km = 5 h

Zoe's average speed
= 274 ÷ 5
= 54⁴₅ km/h

Answer(s): 54⁴₅ km/h