Natalie left home at 11.15 a.m. and drove towards the countryside. 2 hours later, her cousin left their home and drove towards the same countryside at 97 km/h. When the cousin reached the countryside at 4.15 p.m., Natalie had another 2 km to travel. What was Natalie’s average speed? Express your answer in mixed number.
Time that the Natalie's cousin started driving = 1.15 p.m.
Duration that Natalie's cousin drove from 1.15 p.m. to 4.15 p.m. = 3 h

Distance that Natalie's cousin travelled
= 3 x 97
= 291 km

Distance that Natalie travelled by the time her cousin reached the city
= 291 - 2
= 289 km

Time that Natalie took to travel 289 km = 5 h

Natalie's average speed
= 289 ÷ 5
= 57⁴₅ km/h

Answer(s): 57⁴₅ km/h