Gabriel took 6 hours to travel from Country K to Country L at 70 km/h. Then he travelled from Country L to another country at 1.3 times his original speed. 65% of the distance from Country K to Country L is equal to ¹₆ of the distance from Country L to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country K to Country L
= 6 x 70
= 420 km

Speed from Country L to another country
= 1.3 x 70
= 91 km/h

65% = ⁶⁵₁₀₀ = ¹³₆

¹³₂₀ Distance from Country K to Country L = ¹₆ Distance from Country L to next country
¹³₂₀ Distance from Country K to Country L = ¹³₇₈ Distance from Country L to next country

20 u = 420
1 u = 420 ÷ 20 = 21

Distance from Country L to the next country
= 78 u
= 78 x 21
= 1638 km

Time taken from Country L to the next country
= 1638 ÷ 91
= 18 h

Total distance of the whole journey
= 420 + 1638
= 2058 km

Total time taken for the whole journey = 6 + 18 = 24 h

Average speed of the whole journey
= 2058 ÷ 24
= 85 ¹⁸₂₄
= 85 ³₄ km/h

Answer(s): 85 ³₄ km/h