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A man on tour travels 160 km by car at 64 km/hr and another 160 km by bus at 80 km/hr. The average speed for the whole journey is :
Answer & Solution
Correct Answer:
Option
C
Total time taken :
$$\eqalign{ & = \left( {\frac{{160}}{{64}} + \frac{{160}}{{80}}} \right){\text{ hrs}} \cr & = \frac{9}{2}{\text{ hrs}} \cr} $$
∴ Average speed :
$$\eqalign{ & = \left( {320 \times \frac{2}{9}} \right){\text{ km/hr}} \cr & = 71.11{\text{ km/hr}} \cr} $$
$$\eqalign{ & = \left( {\frac{{160}}{{64}} + \frac{{160}}{{80}}} \right){\text{ hrs}} \cr & = \frac{9}{2}{\text{ hrs}} \cr} $$
∴ Average speed :
$$\eqalign{ & = \left( {320 \times \frac{2}{9}} \right){\text{ km/hr}} \cr & = 71.11{\text{ km/hr}} \cr} $$
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