Gabriel took 6 hours to travel from Country D to Country E at 80 km/h. Then he travelled from Country E to another country at 1.2 times his original speed. 60% 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 80
= 480 km

Speed from Country E to another country
= 1.2 x 80
= 96 km/h

60% = ⁶⁰₁₀₀ = ³₆

³₅ Distance from Country D to Country E = ¹₄ Distance from Country E to next country
³₅ Distance from Country D to Country E = ³₁₂ Distance from Country E to next country

5 u = 480
1 u = 480 ÷ 5 = 96

Distance from Country E to the next country
= 12 u
= 12 x 96
= 1152 km

Time taken from Country E to the next country
= 1152 ÷ 96
= 12 h

Total distance of the whole journey
= 480 + 1152
= 1632 km

Total time taken for the whole journey = 6 + 12 = 18 h

Average speed of the whole journey
= 1632 ÷ 18
= 90 ¹²₁₈
= 90 ²₃ km/h

Answer(s): 90 ²₃ km/h