Linda left home at 11.55 a.m. and drove towards the countryside. 2 hours later, her mother left their home and drove towards the same countryside at 97 km/h. When the mother reached the countryside at 6.55 p.m., Linda had another 2 km to travel. What was Linda’s average speed? Express your answer in mixed number.
Time that the Linda's mother started driving = 1.55 p.m.
Duration that Linda's mother drove from 1.55 p.m. to 6.55 p.m. = 5 h

Distance that Linda's mother travelled
= 5 x 97
= 485 km

Distance that Linda travelled by the time her mother reached the city
= 485 - 2
= 483 km

Time that Linda took to travel 483 km = 7 h

Linda's average speed
= 483 ÷ 7
= 69 km/h

Answer(s): 69 km/h