ABC26GN3672 · Time and Distance
Subject: General Aptitude · Chapter: Time and Distance · Exam: 2005 · Marks: · Difficulty:
A car travelling with $\frac{5}{7}$ of its actual speed covers 42 km in 1 hr 40 min 48 sec. Find the actual speed of the car.
(a)$17 \frac{6}{7} \mathrm{km} / \mathrm{hr}$
(b)25 km/hr
(c)30 km/hr
(d)35 km/hr
Answer
Explanation
Time taken $=1 \mathrm{hr} 40 \mathrm{min} 48 \mathrm{sec}$ $$=1 \mathrm{hr} 40 \frac{4}{5} \mathrm{min}=1 \frac{51}{75} \mathrm{hrs}=\frac{126}{75} \mathrm{hrs} .$$ Let the actual speed be $x \mathrm{km} / \mathrm{hr}$. Then, $\frac{5}{7} x \times \frac{126}{75}=42$ or $x=\left(\frac{42 \times 7 \times 75}{5 \times 126}\right)=35 \mathrm{km} / \mathrm{hr}$.
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