ABC26GN5128 · Races and Games of Skill
Subject: General Aptitude · Chapter: Races and Games of Skill · Exam: 2004 · Marks: · Difficulty:
In a 800 metre race, $A$ defeated $B$ by 15 seconds. If A's speed was 8 km/hr, the speed of B was
(a)$\frac{16}{27} \mathrm{km} / \mathrm{hr}$
(b)$\frac{27}{16} \mathrm{km} / \mathrm{hr}$
(c)$7 \frac{17}{25} \mathrm{km} / \mathrm{hr}$
(d)$8 \frac{17}{25} \mathrm{km} / \mathrm{hr}$
Answer
Explanation
A's speed $=8 \mathrm{km} / \mathrm{hr}=\left(8 \times \frac{5}{18}\right) \mathrm{m} / \mathrm{sec}=\frac{20}{9} \mathrm{m} / \mathrm{sec}$. Time taken by $A$ to cover $800 \mathrm{m}=\left(800 \times \frac{9}{20}\right) \mathrm{sec}=360 \mathrm{sec}$. Time taken by $B$ to cover $800 \mathrm{m}=(360+15) \mathrm{sec}$ $$\text { = } 375 \text { sec. }$$ Speed of $$B=\frac{800}{375} \mathrm{m} / \mathrm{sec}=\left(\frac{800}{375} \times \frac{18}{5}\right) \mathrm{km} / \mathrm{hr}=\frac{192}{25} \mathrm{km} / \mathrm{hr}=7 \frac{17}{25} \mathrm{km} / \mathrm{hr} .$$
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