Andy took 4 hours to travel from Country A to Country B at 75 km/h. Then he travelled from Country B to another country at 1.2 times his original speed. 40% of the distance from Country A to Country B is equal to ¹₃ of the distance from Country B to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country A to Country B
= 4 x 75
= 300 km

Speed from Country B to another country
= 1.2 x 75
= 90 km/h

40% = ⁴⁰₁₀₀ = ²₄

²₅ Distance from Country A to Country B = ¹₃ Distance from Country B to next country
²₅ Distance from Country A to Country B = ²₆ Distance from Country B to next country

5 u = 300
1 u = 300 ÷ 5 = 60

Distance from Country B to the next country
= 6 u
= 6 x 60
= 360 km

Time taken from Country B to the next country
= 360 ÷ 90
= 4 h

Total distance of the whole journey
= 300 + 360
= 660 km

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

Average speed of the whole journey
= 660 ÷ 8
= 82 ⁴₈
= 82 ¹₂ km/h

Answer(s): 82 ¹₂ km/h