Question

A boy is running at a speed of $p$ km/hr to cover a distance of $1$ km. But, due to slippery ground, his speed is reduced by $q$ km/hr $(p>q).$ If he takes $r$ hours to cover the distance, then,

• A. $\frac{1}{r}=(p-q)$
• B. $r=(p-q)$
• C. $\frac{1}{r}=(p+q)$
• D. $r=(p+q)$

Answer 1

The correct option is A $\frac{1}{r}=(p-q)$

Running speed = p km/hr, Reduced speed = q km/hr
$\therefore$ Actual speed of the boy = (p - q) km/hr
Time taken = r hours, Distance covered = 1 km.
$\therefore 1=(p-q)r\Rightarrow \frac{1}{r}=(p-q)$