Linda left home at 11.35 a.m. and drove towards the seaside resort. 3 hours later, her cousin left their home and drove towards the same seaside resort at 84 km/h. When the cousin reached the seaside resort at 7.35 p.m., Linda had another 6 km to travel. What was Linda’s average speed? Express your answer in mixed number.
Time that the Linda's cousin started driving = 2.35 p.m.
Duration that Linda's cousin drove from 2.35 p.m. to 7.35 p.m. = 5 h

Distance that Linda's cousin travelled
= 5 x 84
= 420 km

Distance that Linda travelled by the time her cousin reached the city
= 420 - 6
= 414 km

Time that Linda took to travel 414 km = 8 h

Linda's average speed
= 414 ÷ 8
= 51³₄ km/h

Answer(s): 51³₄ km/h