Ryan took 6 hours to travel from Country Z to Country A at 54 km/h. Then he travelled from Country A to another country at 1.5 times his original speed. 25% of the distance from Country Z to Country A is equal to ¹₄ 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
= 6 x 54
= 324 km

Speed from Country A to another country
= 1.5 x 54
= 81 km/h

25% = ²⁵₁₀₀ = ¹₆

¹₄ Distance from Country Z to Country A = ¹₄ Distance from Country A to next country
¹₄ Distance from Country Z to Country A = ¹₄ Distance from Country A to next country

4 u = 324
1 u = 324 ÷ 4 = 81

Distance from Country A to the next country
= 4 u
= 4 x 81
= 324 km

Time taken from Country A to the next country
= 324 ÷ 81
= 4 h

Total distance of the whole journey
= 324 + 324
= 648 km

Total time taken for the whole journey = 6 + 4 = 10 h

Average speed of the whole journey
= 648 ÷ 10
= 64 ⁸₁₀
= 64 ⁴₅ km/h

Answer(s): 64 ⁴₅ km/h