Tom took 4 hours to travel from Country Z to Country A at 50 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 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
= 4 x 50
= 200 km

Speed from Country A to another country
= 1.5 x 50
= 75 km/h

25% = ²⁵₁₀₀ = ¹₄

¹₄ Distance from Country Z to Country A = ¹₆ Distance from Country A to next country
¹₄ Distance from Country Z to Country A = ¹₆ Distance from Country A to next country

4 u = 200
1 u = 200 ÷ 4 = 50

Distance from Country A to the next country
= 6 u
= 6 x 50
= 300 km

Time taken from Country A to the next country
= 300 ÷ 75
= 4 h

Total distance of the whole journey
= 200 + 300
= 500 km

Total time taken for the whole journey = 4 + 4 = 8 h

Average speed of the whole journey
= 500 ÷ 8
= 62 ⁴₈
= 62 ¹₂ km/h

Answer(s): 62 ¹₂ km/h