Oscar took 3 hours to travel from Country W to Country X at 68 km/h. Then he travelled from Country X to another country at 1.5 times his original speed. 50% of the distance from Country W to Country X is equal to ¹₆ of the distance from Country X to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country W to Country X
= 3 x 68
= 204 km

Speed from Country X to another country
= 1.5 x 68
= 102 km/h

50% = ⁵⁰₁₀₀ = ¹₃

¹₂ Distance from Country W to Country X = ¹₆ Distance from Country X to next country
¹₂ Distance from Country W to Country X = ¹₆ Distance from Country X to next country

2 u = 204
1 u = 204 ÷ 2 = 102

Distance from Country X to the next country
= 6 u
= 6 x 102
= 612 km

Time taken from Country X to the next country
= 612 ÷ 102
= 6 h

Total distance of the whole journey
= 204 + 612
= 816 km

Total time taken for the whole journey = 3 + 6 = 9 h

Average speed of the whole journey
= 816 ÷ 9
= 90 ⁶₉
= 90 ²₃ km/h

Answer(s): 90 ²₃ km/h