Howard took 6 hours to travel from Country V to Country W at 70 km/h. Then he travelled from Country W to another country at 1.2 times his original speed. 70% of the distance from Country V to Country W is equal to ¹₆ of the distance from Country W to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country V to Country W
= 6 x 70
= 420 km

Speed from Country W to another country
= 1.2 x 70
= 84 km/h

70% = ⁷⁰₁₀₀ = ⁷₆

⁷₁₀ Distance from Country V to Country W = ¹₆ Distance from Country W to next country
⁷₁₀ Distance from Country V to Country W = ⁷₄₂ Distance from Country W to next country

10 u = 420
1 u = 420 ÷ 10 = 42

Distance from Country W to the next country
= 42 u
= 42 x 42
= 1764 km

Time taken from Country W to the next country
= 1764 ÷ 84
= 21 h

Total distance of the whole journey
= 420 + 1764
= 2184 km

Total time taken for the whole journey = 6 + 21 = 27 h

Average speed of the whole journey
= 2184 ÷ 27
= 80 ²⁴₂₇
= 80 ⁸₉ km/h

Answer(s): 80 ⁸₉ km/h