A car was on its way from Town M to Town N. After covering ⁷₉ of its journey, it passed a van which was travelling at an average speed of 61 km/h. 4 hours later, the car reached its destination, but the van was still 30 km from Town N. If the car had also started from Town M, how long would it take to travel from Town M to Town N? Express your answer as a mixed number.
Fraction of the journey left after the car passed the van
= 1 - ⁷₉
= ²₉

²₉ of the car's journey = (4 x 61) + 30 = 274 km
¹₉ of the car's journey = 274 ÷ 2 = 137 km
⁹₉ of the car 's journey = 9 x 137 = 1233 km

Speed of the car
= 274 ÷ 4
= 68.5 km/h

Time taken for the car to reach Town N
= 1233 ÷ 68.5
= 18 h

Answer(s): 18 h