Zara left home at 11.35 a.m. and drove towards the seaside resort. 2 hours later, her older sister left their home and drove towards the same seaside resort at 85 km/h. When the older sister reached the seaside resort at 4.35 p.m., Zara had another 3 km to travel. What was Zara’s average speed? Express your answer in mixed number.
Time that the Zara's older sister started driving = 1.35 p.m.
Duration that Zara's older sister drove from 1.35 p.m. to 4.35 p.m. = 3 h

Distance that Zara's older sister travelled
= 3 x 85
= 255 km

Distance that Zara travelled by the time her older sister reached the city
= 255 - 3
= 252 km

Time that Zara took to travel 252 km = 5 h

Zara's average speed
= 252 ÷ 5
= 50²₅ km/h

Answer(s): 50²₅ km/h