Luke took 6 hours to travel from Country D to Country E at 64 km/h. Then he travelled from Country E to another country at 1.5 times his original speed. 50% of the distance from Country D to Country E is equal to ¹₄ of the distance from Country E to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country D to Country E
= 6 x 64
= 384 km

Speed from Country E to another country
= 1.5 x 64
= 96 km/h

50% = ⁵⁰₁₀₀ = ¹₆

¹₂ Distance from Country D to Country E = ¹₄ Distance from Country E to next country
¹₂ Distance from Country D to Country E = ¹₄ Distance from Country E to next country

2 u = 384
1 u = 384 ÷ 2 = 192

Distance from Country E to the next country
= 4 u
= 4 x 192
= 768 km

Time taken from Country E to the next country
= 768 ÷ 96
= 8 h

Total distance of the whole journey
= 384 + 768
= 1152 km

Total time taken for the whole journey = 6 + 8 = 14 h

Average speed of the whole journey
= 1152 ÷ 14
= 82 ⁴₁₄
= 82 ²₇ km/h

Answer(s): 82 ²₇ km/h