Mrs Song left home at 7 a.m. and drove towards the city. 1³₄ hour later, Mr Song left the house and drove at an average speed of 96 km/h towards the city. When Mr Song reached his destination at 2 p.m., Mrs Song was 29 km away from the city. Find Mrs Song’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
³₄ h = ³₄ x 60 = 45 min
1³₄ = 1 h 45 min

1 h 45 min after 7 a.m. = 8.45 a.m.

Time that Mr Song left the house = 8.45 a.m.

Time that Mr Song took from 8.45 a.m. to 2 p.m. to reach his destination = 5 h 15 min

1 min = ¹₆₀ h
15 min = ¹⁵₆₀ h = ¹₄ h
5 h 15 min = 5¹₄ h

Distance that Mr Song drove
= 5¹₄ x 96
= 504 km

Distance that Mrs Song drove when Mr Song reached
= 504 - 29 
= 475 km

Time that Mrs Song took to travel from 7 a.m. to 2 p.m. = 7 h

Mrs Song's average speed
= 475 ÷ 7
= 67⁶₇ km/h

Answer(s): 67⁶₇ km/h