Warren took 4 hours to travel from Country U to Country V at 65 km/h. Then he travelled from Country V to another country at 1.2 times his original speed. 30% of the distance from Country U to Country V is equal to ¹₄ of the distance from Country V to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country U to Country V
= 4 x 65
= 260 km

Speed from Country V to another country
= 1.2 x 65
= 78 km/h

30% = ³⁰₁₀₀ = ³₄

³₁₀ Distance from Country U to Country V = ¹₄ Distance from Country V to next country
³₁₀ Distance from Country U to Country V = ³₁₂ Distance from Country V to next country

10 u = 260
1 u = 260 ÷ 10 = 26

Distance from Country V to the next country
= 12 u
= 12 x 26
= 312 km

Time taken from Country V to the next country
= 312 ÷ 78
= 4 h

Total distance of the whole journey
= 260 + 312
= 572 km

Total time taken for the whole journey = 4 + 4 = 8 h

Average speed of the whole journey
= 572 ÷ 8
= 71 ⁴₈
= 71 ¹₂ km/h

Answer(s): 71 ¹₂ km/h