Dylan took 3 hours to travel from Country B to Country C at 56 km/h. Then he travelled from Country C to another country at 1.5 times his original speed. 50% of the distance from Country B to Country C is equal to ¹₅ of the distance from Country C to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country B to Country C
= 3 x 56
= 168 km

Speed from Country C to another country
= 1.5 x 56
= 84 km/h

50% = ⁵⁰₁₀₀ = ¹₃

¹₂ Distance from Country B to Country C = ¹₅ Distance from Country C to next country
¹₂ Distance from Country B to Country C = ¹₅ Distance from Country C to next country

2 u = 168
1 u = 168 ÷ 2 = 84

Distance from Country C to the next country
= 5 u
= 5 x 84
= 420 km

Time taken from Country C to the next country
= 420 ÷ 84
= 5 h

Total distance of the whole journey
= 168 + 420
= 588 km

Total time taken for the whole journey = 3 + 5 = 8 h

Average speed of the whole journey
= 588 ÷ 8
= 73 ⁴₈
= 73 ¹₂ km/h

Answer(s): 73 ¹₂ km/h