Albert took 4 hours to travel from Country G to Country H at 78 km/h. Then he travelled from Country H to another country at 1.5 times his original speed. 50% of the distance from Country G to Country H is equal to ¹₃ of the distance from Country H to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country G to Country H
= 4 x 78
= 312 km

Speed from Country H to another country
= 1.5 x 78
= 117 km/h

50% = ⁵⁰₁₀₀ = ¹₄

¹₂ Distance from Country G to Country H = ¹₃ Distance from Country H to next country
¹₂ Distance from Country G to Country H = ¹₃ Distance from Country H to next country

2 u = 312
1 u = 312 ÷ 2 = 156

Distance from Country H to the next country
= 3 u
= 3 x 156
= 468 km

Time taken from Country H to the next country
= 468 ÷ 117
= 4 h

Total distance of the whole journey
= 312 + 468
= 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