Reggie took 3 hours to travel from Country Z to Country A at 52 km/h. Then he travelled from Country A to another country at 1.5 times his original speed. 50% of the distance from Country Z to Country A is equal to ¹₆ of the distance from Country A to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country Z to Country A
= 3 x 52
= 156 km

Speed from Country A to another country
= 1.5 x 52
= 78 km/h

50% = ⁵⁰₁₀₀ = ¹₃

¹₂ Distance from Country Z to Country A = ¹₆ Distance from Country A to next country
¹₂ Distance from Country Z to Country A = ¹₆ Distance from Country A to next country

2 u = 156
1 u = 156 ÷ 2 = 78

Distance from Country A to the next country
= 6 u
= 6 x 78
= 468 km

Time taken from Country A to the next country
= 468 ÷ 78
= 6 h

Total distance of the whole journey
= 156 + 468
= 624 km

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

Average speed of the whole journey
= 624 ÷ 9
= 69 ³₉
= 69 ¹₃ km/h

Answer(s): 69 ¹₃ km/h