Archie took 4 hours to travel from Country U to Country V at 60 km/h. Then he travelled from Country V to another country at 1.3 times his original speed. 65% of the distance from Country U to Country V is equal to ¹₆ 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 60
= 240 km

Speed from Country V to another country
= 1.3 x 60
= 78 km/h

65% = ⁶⁵₁₀₀ = ¹³₄

¹³₂₀ Distance from Country U to Country V = ¹₆ Distance from Country V to next country
¹³₂₀ Distance from Country U to Country V = ¹³₇₈ Distance from Country V to next country

20 u = 240
1 u = 240 ÷ 20 = 12

Distance from Country V to the next country
= 78 u
= 78 x 12
= 936 km

Time taken from Country V to the next country
= 936 ÷ 78
= 12 h

Total distance of the whole journey
= 240 + 936
= 1176 km

Total time taken for the whole journey = 4 + 12 = 16 h

Average speed of the whole journey
= 1176 ÷ 16
= 73 ⁸₁₆
= 73 ¹₂ km/h

Answer(s): 73 ¹₂ km/h