Anna left home at 11.40 a.m. and drove towards the seaside resort. 3 hours later, her father left their home and drove towards the same seaside resort at 97 km/h. When the father reached the seaside resort at 6.40 p.m., Anna had another 3 km to travel. What was Anna’s average speed? Express your answer in mixed number.
Time that the Anna's father started driving = 2.40 p.m.
Duration that Anna's father drove from 2.40 p.m. to 6.40 p.m. = 4 h

Distance that Anna's father travelled
= 4 x 97
= 388 km

Distance that Anna travelled by the time her father reached the city
= 388 - 3
= 385 km

Time that Anna took to travel 385 km = 7 h

Anna's average speed
= 385 ÷ 7
= 55 km/h

Answer(s): 55 km/h