Howard took 3 hours to travel from Country S to Country T at 72 km/h. Then he travelled from Country T to another country at 1.5 times his original speed. 50% of the distance from Country S to Country T is equal to ¹₅ of the distance from Country T to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country S to Country T
= 3 x 72
= 216 km

Speed from Country T to another country
= 1.5 x 72
= 108 km/h

50% = ⁵⁰₁₀₀ = ¹₃

¹₂ Distance from Country S to Country T = ¹₅ Distance from Country T to next country
¹₂ Distance from Country S to Country T = ¹₅ Distance from Country T to next country

2 u = 216
1 u = 216 ÷ 2 = 108

Distance from Country T to the next country
= 5 u
= 5 x 108
= 540 km

Time taken from Country T to the next country
= 540 ÷ 108
= 5 h

Total distance of the whole journey
= 216 + 540
= 756 km

Total time taken for the whole journey = 3 + 5 = 8 h

Average speed of the whole journey
= 756 ÷ 8
= 94 ⁴₈
= 94 ¹₂ km/h

Answer(s): 94 ¹₂ km/h