Carl took 4 hours to travel from Country U to Country V at 50 km/h. Then he travelled from Country V to another country at 1.2 times his original speed. 60% 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 50
= 200 km

Speed from Country V to another country
= 1.2 x 50
= 60 km/h

60% = ⁶⁰₁₀₀ = ³₄

³₅ Distance from Country U to Country V = ¹₄ Distance from Country V to next country
³₅ Distance from Country U to Country V = ³₁₂ Distance from Country V to next country

5 u = 200
1 u = 200 ÷ 5 = 40

Distance from Country V to the next country
= 12 u
= 12 x 40
= 480 km

Time taken from Country V to the next country
= 480 ÷ 60
= 8 h

Total distance of the whole journey
= 200 + 480
= 680 km

Total time taken for the whole journey = 4 + 8 = 12 h

Average speed of the whole journey
= 680 ÷ 12
= 56 ⁸₁₂
= 56 ²₃ km/h

Answer(s): 56 ²₃ km/h