Eric took 4 hours to travel from Country V to Country W at 75 km/h. Then he travelled from Country W to another country at 1.6 times his original speed. 40% of the distance from Country V to Country W is equal to ¹₄ 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
= 4 x 75
= 300 km

Speed from Country W to another country
= 1.6 x 75
= 120 km/h

40% = ⁴⁰₁₀₀ = ²₄

²₅ Distance from Country V to Country W = ¹₄ Distance from Country W to next country
²₅ Distance from Country V to Country W = ²₈ Distance from Country W to next country

5 u = 300
1 u = 300 ÷ 5 = 60

Distance from Country W to the next country
= 8 u
= 8 x 60
= 480 km

Time taken from Country W to the next country
= 480 ÷ 120
= 4 h

Total distance of the whole journey
= 300 + 480
= 780 km

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

Average speed of the whole journey
= 780 ÷ 8
= 97 ⁴₈
= 97 ¹₂ km/h

Answer(s): 97 ¹₂ km/h