Warren took 4 hours to travel from Country T to Country U at 55 km/h. Then he travelled from Country U to another country at 1.2 times his original speed. 70% of the distance from Country T to Country U is equal to ¹₆ of the distance from Country U to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country T to Country U
= 4 x 55
= 220 km

Speed from Country U to another country
= 1.2 x 55
= 66 km/h

70% = ⁷⁰₁₀₀ = ⁷₄

⁷₁₀ Distance from Country T to Country U = ¹₆ Distance from Country U to next country
⁷₁₀ Distance from Country T to Country U = ⁷₄₂ Distance from Country U to next country

10 u = 220
1 u = 220 ÷ 10 = 22

Distance from Country U to the next country
= 42 u
= 42 x 22
= 924 km

Time taken from Country U to the next country
= 924 ÷ 66
= 14 h

Total distance of the whole journey
= 220 + 924
= 1144 km

Total time taken for the whole journey = 4 + 14 = 18 h

Average speed of the whole journey
= 1144 ÷ 18
= 63 ¹⁰₁₈
= 63 ⁵₉ km/h

Answer(s): 63 ⁵₉ km/h