Subject: General Aptitude · Chapter: Time and Distance · Exam: · Marks: · Difficulty:
A student goes to school at the rate of $2 \frac{1}{2} \mathrm{km} / \mathrm{h}$ and reaches 6 min late. If he travels at the speed of 3km/h he is 10 min early. What is the distance to the school ? [SSC-CHSL (10+2) Exam, 2015]
(a)4 km
(b)$3 \frac{1}{4} \mathrm{km}$
(c)1 km
(d)$3 \frac{1}{2} \mathrm{km}$
Answer
Answer (as printed): A
Explanation
Let the distance between school and home be $D$. According to the given information, $$\frac{D}{2\frac{1}{2}}-\frac{D}{3}=16\text{ minutes}$$ $$\therefore \frac{2D}{5}-\frac{D}{3}=\frac{16}{60}$$ $$\Rightarrow \frac{6D-5D}{15}=\frac{16}{60}$$ $$\Rightarrow D=\frac{16}{60}\times15=4\text{ km}$$
Explanation as extracted from the printed page; notation may be imperfect.