Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: 2006 · Marks: · Difficulty:
The H.C.F. and L.C.M. of two numbers are 21 and 4641 respectively. If one of the numbers lies between 200 and 300, the two numbers are
(a)273, 357
(b)273, 359
(c)273, 361
(d)273, 363
Answer
Answer (as printed): A
Explanation
Product of numbers $=21 \times 4641=97461$. Let the numbers be $21 a$ and $21 b$. Then, $21 a \times 21 b=97461 \Rightarrow a b=221$. Now, co-primes with product 221 are $(1,221)$ and (13, 17). So, the numbers are $(21 \times 1,21 \times 221)$ and $(21 \times 13,21 \times$ 17). Since one number lies between 200 and 300, the suitable pair is (273, 357).
Explanation as extracted from the printed page; notation may be imperfect.