Gabriel took 5 hours to travel from Country B to Country C at 60 km/h. Then he travelled from Country C to another country at 1.3 times his original speed. 65% of the distance from Country B to Country C is equal to ¹₆ of the distance from Country C to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country B to Country C
= 5 x 60
= 300 km

Speed from Country C to another country
= 1.3 x 60
= 78 km/h

65% = ⁶⁵₁₀₀ = ¹³₅

¹³₂₀ Distance from Country B to Country C = ¹₆ Distance from Country C to next country
¹³₂₀ Distance from Country B to Country C = ¹³₇₈ Distance from Country C to next country

20 u = 300
1 u = 300 ÷ 20 = 15

Distance from Country C to the next country
= 78 u
= 78 x 15
= 1170 km

Time taken from Country C to the next country
= 1170 ÷ 78
= 15 h

Total distance of the whole journey
= 300 + 1170
= 1470 km

Total time taken for the whole journey = 5 + 15 = 20 h

Average speed of the whole journey
= 1470 ÷ 20
= 73 ¹⁰₂₀
= 73 ¹₂ km/h

Answer(s): 73 ¹₂ km/h