Daniel took 4 hours to travel from Country P to Country Q at 65 km/h. Then he travelled from Country Q to another country at 1.6 times his original speed. 50% of the distance from Country P to Country Q is equal to ¹₄ of the distance from Country Q to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country P to Country Q
= 4 x 65
= 260 km

Speed from Country Q to another country
= 1.6 x 65
= 104 km/h

50% = ⁵⁰₁₀₀ = ¹₄

¹₂ Distance from Country P to Country Q = ¹₄ Distance from Country Q to next country
¹₂ Distance from Country P to Country Q = ¹₄ Distance from Country Q to next country

2 u = 260
1 u = 260 ÷ 2 = 130

Distance from Country Q to the next country
= 4 u
= 4 x 130
= 520 km

Time taken from Country Q to the next country
= 520 ÷ 104
= 5 h

Total distance of the whole journey
= 260 + 520
= 780 km

Total time taken for the whole journey = 4 + 5 = 9 h

Average speed of the whole journey
= 780 ÷ 9
= 86 ⁶₉
= 86 ²₃ km/h

Answer(s): 86 ²₃ km/h