Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: · Marks: · Difficulty:
Three persons walking around a circular track complete their respective single revolutions in $15 \frac{1}{6}$ seconds, $16 \frac{1}{4}$ seconds and $18 \frac{2}{3}$ seconds respectively. They will be again together at the common starting point after an hour and
(a)10 seconds
(b)20 seconds
(c)30 seconds
(d)40 seconds
Answer
Answer (as printed): D
Explanation
L.C.M. of $\frac{91}{6}, \frac{65}{4}$ and $\frac{56}{3}=\frac{\text { L.C.M. of } 91,65,56}{\text { H.C.F. of } 6,4,3}=3640$. So, the three persons will be together at the starting point in 3640 sec i.e., 1 hour 40 seconds.
Explanation as extracted from the printed page; notation may be imperfect.