Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: 2007 · Marks: · Difficulty:
The L.C.M. and ratio of four numbers are 630 and 2: 3: 5: 7 respectively. The difference between the greatest and least numbers is
(a)6
(b)14
(c)15
(d)21
Answer
Answer (as printed): C
Explanation
Let the numbers be $2 x, 3 x, 5 x$ and $7 x$ respectively. Then, their L.C.M. $=(2 \times 3 \times 5 \times 7) x=210 x$. $[\because 2,3,5,7$ are prime numbers $]$ So, $210 x=630$ or $x=3$. ∴ The numbers are 6, 9, 15 and 21. Required difference $=21-6=15$.
Explanation as extracted from the printed page; notation may be imperfect.