Nick took 5 hours to travel from Country P to Country Q at 70 km/h. Then he travelled from Country Q to another country at 1.5 times his original speed. 60% of the distance from Country P to Country Q is equal to ¹₅ of the distance from Country Q to the next country. Find the average speed for the whole journey and express it as a mixed number.
Distance he travelled from Country P to Country Q
= 5 x 70
= 350 km

Speed from Country Q to another country
= 1.5 x 70
= 105 km/h

60% = ⁶⁰₁₀₀ = ³₅

³₅ Distance from Country P to Country Q = ¹₅ Distance from Country Q to next country
³₅ Distance from Country P to Country Q = ³₁₅ Distance from Country Q to next country

5 u = 350
1 u = 350 ÷ 5 = 70

Distance from Country Q to the next country
= 15 u
= 15 x 70
= 1050 km

Time taken from Country Q to the next country
= 1050 ÷ 105
= 10 h

Total distance of the whole journey
= 350 + 1050
= 1400 km

Total time taken for the whole journey = 5 + 10 = 15 h

Average speed of the whole journey
= 1400 ÷ 15
= 93 ⁵₁₅
= 93 ¹₃ km/h

Answer(s): 93 ¹₃ km/h