Xavier took 5 hours to travel from Country F to Country G at 66 km/h. Then he travelled from Country G to another country at 1.5 times his original speed. 30% of the distance from Country F to Country G is equal to ¹₅ of the distance from Country G to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country F to Country G
= 5 x 66
= 330 km

Speed from Country G to another country
= 1.5 x 66
= 99 km/h

30% = ³⁰₁₀₀ = ³₅

³₁₀ Distance from Country F to Country G = ¹₅ Distance from Country G to next country
³₁₀ Distance from Country F to Country G = ³₁₅ Distance from Country G to next country

10 u = 330
1 u = 330 ÷ 10 = 33

Distance from Country G to the next country
= 15 u
= 15 x 33
= 495 km

Time taken from Country G to the next country
= 495 ÷ 99
= 5 h

Total distance of the whole journey
= 330 + 495
= 825 km

Total time taken for the whole journey = 5 + 5 = 10 h

Average speed of the whole journey
= 825 ÷ 10
= 82 ⁵₁₀
= 82 ¹₂ km/h

Answer(s): 82 ¹₂ km/h