Question

Two guns are fired from the same place at an interval of $6$ minutes. A person approaching the place observes that $5$ minutes $52$ seconds have elapsed between the hearings of the sound of the two guns. If the velocity of the sound is $330$ m/sec, then at what speed the person was approaching that place?

• A. $25$ kmph
• B. $27$ kmph
• C. $30$ kmph
• D. $36$ kmph

Answer 1

The correct option is B $27$ kmph

Difference of time
$=6\text{minutes}-5\text{minutes}52\text{seconds}$
$=8\text{seconds}$
Distance covered by person in $5\text{min}52\text{sec}$
$=$ Distance covered by sound in $8\text{seconds}$
$=330\times 8=2640$ m

$\therefore$ Speed of person $=\frac{2640\text{m}}{5\text{minutes}52\text{seconds}}$
$=\frac{2640}{352}$ m/sec
$=\frac{2640}{352}\times \frac{18}{5}$ kmph
$=27$ kmph