Mrs Peh left home at 10 a.m. and drove towards the city. 1⁵₆ hour later, Mr Peh left the house and drove at an average speed of 108 km/h towards the city. When Mr Peh reached his destination at 3 p.m., Mrs Peh was 13 km away from the city. Find Mrs Peh’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
⁵₆ h = ⁵₆ x 60 = 50 min
1⁵₆ = 1 h 50 min

1 h 50 min after 10 a.m. = 11.50 a.m.

Time that Mr Peh left the house = 11.50 a.m.

Time that Mr Peh took from 11.50 a.m. to 3 p.m. to reach his destination = 3 h 10 min

1 min = ¹₆₀ h
10 min = ¹⁰₆₀ h = ¹₆ h
3 h 10 min = 3¹₆ h

Distance that Mr Peh drove
= 3¹₆ x 108
= 342 km

Distance that Mrs Peh drove when Mr Peh reached
= 342 - 13 
= 329 km

Time that Mrs Peh took to travel from 10 a.m. to 3 p.m. = 5 h

Mrs Peh's average speed
= 329 ÷ 5
= 65⁴₅ km/h

Answer(s): 65⁴₅ km/h