Will took 6 hours to travel from Country C to Country D at 62 km/h. Then he travelled from Country D to another country at 1.5 times his original speed. 50% of the distance from Country C to Country D is equal to ¹₃ of the distance from Country D to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country C to Country D
= 6 x 62
= 372 km

Speed from Country D to another country
= 1.5 x 62
= 93 km/h

50% = ⁵⁰₁₀₀ = ¹₆

¹₂ Distance from Country C to Country D = ¹₃ Distance from Country D to next country
¹₂ Distance from Country C to Country D = ¹₃ Distance from Country D to next country

2 u = 372
1 u = 372 ÷ 2 = 186

Distance from Country D to the next country
= 3 u
= 3 x 186
= 558 km

Time taken from Country D to the next country
= 558 ÷ 93
= 6 h

Total distance of the whole journey
= 372 + 558
= 930 km

Total time taken for the whole journey = 6 + 6 = 12 h

Average speed of the whole journey
= 930 ÷ 12
= 77 ⁶₁₂
= 77 ¹₂ km/h

Answer(s): 77 ¹₂ km/h