Linda left home at 11.40 a.m. and drove towards the city. 3 hours later, her grandmother left their home and drove towards the same city at 99 km/h. When the grandmother reached the city at 7.40 p.m., Linda had another 3 km to travel. What was Linda’s average speed? Express your answer in mixed number.
Time that the Linda's grandmother started driving = 2.40 p.m.
Duration that Linda's grandmother drove from 2.40 p.m. to 7.40 p.m. = 5 h

Distance that Linda's grandmother travelled
= 5 x 99
= 495 km

Distance that Linda travelled by the time her grandmother reached the city
= 495 - 3
= 492 km

Time that Linda took to travel 492 km = 8 h

Linda's average speed
= 492 ÷ 8
= 61¹₂ km/h

Answer(s): 61¹₂ km/h