Mrs Ma left home at 8 a.m. and drove towards the city. 1⁵₆ hour later, Mr Ma left the house and drove at an average speed of 101 km/h towards the city. When Mr Ma reached his destination at 1 p.m., Mrs Ma was 18 km away from the city. Find Mrs Ma’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 8 a.m. = 9.50 a.m.

Time that Mr Ma left the house = 9.50 a.m.

Time that Mr Ma took from 9.50 a.m. to 1 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 Ma drove
= 3¹₆ x 101
= 319⁵₆ km

Distance that Mrs Ma drove when Mr Ma reached
= 319⁵₆ - 18 
= 301⁵₆ km

Time that Mrs Ma took to travel from 8 a.m. to 1 p.m. = 5 h

Mrs Ma's average speed
= 301⁵₆ ÷ 5
= 60¹¹₃₀ km/h

Answer(s): 60¹¹₃₀ km/h