Dana left home at 11.50 a.m. and drove towards the countryside. 3 hours later, her cousin left their home and drove towards the same countryside at 98 km/h. When the cousin reached the countryside at 7.50 p.m., Dana had another 4 km to travel. What was Dana’s average speed? Express your answer in mixed number.
Time that the Dana's cousin started driving = 2.50 p.m.
Duration that Dana's cousin drove from 2.50 p.m. to 7.50 p.m. = 5 h

Distance that Dana's cousin travelled
= 5 x 98
= 490 km

Distance that Dana travelled by the time her cousin reached the city
= 490 - 4
= 486 km

Time that Dana took to travel 486 km = 8 h

Dana's average speed
= 486 ÷ 8
= 60³₄ km/h

Answer(s): 60³₄ km/h