ABC26GN5125 · Races and Games of Skill
Subject: General Aptitude · Chapter: Races and Games of Skill · Exam: 2007 · Marks: · Difficulty:
$A$ and $B$ take part in a 100 m race. $A$ runs at 5 km an hour. $A$ gives $B$ a start of 8 m and still beats him by 8 seconds. The speed of $B$ is
(a)4.45 km/hr
(b)4.14 km/hr
(c)4.15 km/hr
(d)4.25 km/hr
Answer
Explanation
$A^{\prime} \mathrm{s}$ speed $=5 \mathrm{km} / \mathrm{hr}=\left(5 \times \frac{5}{18}\right) \mathrm{m} / \mathrm{sec}=\frac{25}{18} \mathrm{m} / \mathrm{sec}$. Time taken by $A$ to cover $100 \mathrm{m}=\left(100 \times \frac{18}{25}\right) \mathrm{sec}=72 \mathrm{sec}$. Time taken by $B$ to cover $92 \mathrm{m}=(72+8) \mathrm{sec}=80 \mathrm{sec}$. $B^{\prime}$ s speed = $$\left(\frac{92}{80}\right) \mathrm{m} / \mathrm{sec}=\left(\frac{92}{80} \times \frac{18}{5}\right) \mathrm{km} / \mathrm{hr}=\frac{414}{100} \mathrm{km} / \mathrm{hr}=4.14 \mathrm{km} / \mathrm{hr} .$$
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