Sam took 4 hours to travel from Country P to Country Q at 50 km/h. Then he travelled from Country Q to another country at 1.5 times his original speed. 25% of the distance from Country P to Country Q is equal to ¹₃ 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
= 4 x 50
= 200 km

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

25% = ²⁵₁₀₀ = ¹₄

¹₄ Distance from Country P to Country Q = ¹₃ Distance from Country Q to next country
¹₄ Distance from Country P to Country Q = ¹₃ Distance from Country Q to next country

4 u = 200
1 u = 200 ÷ 4 = 50

Distance from Country Q to the next country
= 3 u
= 3 x 50
= 150 km

Time taken from Country Q to the next country
= 150 ÷ 75
= 2 h

Total distance of the whole journey
= 200 + 150
= 350 km

Total time taken for the whole journey = 4 + 2 = 6 h

Average speed of the whole journey
= 350 ÷ 6
= 58 ²₆
= 58 ¹₃ km/h

Answer(s): 58 ¹₃ km/h