Zara left home at 10.25 a.m. and drove towards the city. 3 hours later, her grandfather left their home and drove towards the same city at 100 km/h. When the grandfather reached the city at 6.25 p.m., Zara had another 6 km to travel. What was Zara’s average speed? Express your answer in mixed number.
Time that the Zara's grandfather started driving = 1.25 p.m.
Duration that Zara's grandfather drove from 1.25 p.m. to 6.25 p.m. = 5 h

Distance that Zara's grandfather travelled
= 5 x 100
= 500 km

Distance that Zara travelled by the time her grandfather reached the city
= 500 - 6
= 494 km

Time that Zara took to travel 494 km = 8 h

Zara's average speed
= 494 ÷ 8
= 61³₄ km/h

Answer(s): 61³₄ km/h