Xavier took 6 hours to travel from Country N to Country P at 55 km/h. Then he travelled from Country P to another country at 1.6 times his original speed. 40% of the distance from Country N to Country P is equal to ¹₄ of the distance from Country P to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country N to Country P
= 6 x 55
= 330 km

Speed from Country P to another country
= 1.6 x 55
= 88 km/h

40% = ⁴⁰₁₀₀ = ²₆

²₅ Distance from Country N to Country P = ¹₄ Distance from Country P to next country
²₅ Distance from Country N to Country P = ²₈ Distance from Country P to next country

5 u = 330
1 u = 330 ÷ 5 = 66

Distance from Country P to the next country
= 8 u
= 8 x 66
= 528 km

Time taken from Country P to the next country
= 528 ÷ 88
= 6 h

Total distance of the whole journey
= 330 + 528
= 858 km

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

Average speed of the whole journey
= 858 ÷ 12
= 71 ⁶₁₂
= 71 ¹₂ km/h

Answer(s): 71 ¹₂ km/h