Aptitude - Problems on H.C.F and L.C.M - Discussion

Discussion Forum : Problems on H.C.F and L.C.M - General Questions (Q.No. 2)
2.
The H.C.F. of two numbers is 23 and the other two factors of their L.C.M. are 13 and 14. The larger of the two numbers is:
276
299
322
345
Answer: Option
Explanation:

Clearly, the numbers are (23 x 13) and (23 x 14).

Larger number = (23 x 14) = 322.

Discussion:
153 comments Page 9 of 16.

Narendra said:   9 years ago
Not getting this. Please can anybody explain me clearly?

Rajesh Reddy said:   9 years ago
Statement 1:- We know that if 2 numbers are co-primes, then their LCM is equal to their product.
Statement 2:- We also know that if 2 numbers are co-primes,then their HCF is 1.

In the given question, 13 and 14 are the factors of the LCM of 2 numbers. Therefore it is understood that the 2 numbers are the multiples of 13 and 14.

23 is the HCF of 2 numbers. Therefore 2 numbers are not co-primes.
Given that 23 is the common factor of the 2 numbers - 23x13 = 299 and 23 x 14 = 322.
LCM of 299 and 322 = 4186.13 and 14 are the factors of 4186.
HCF of 299 and 322 = 23.
Therefore, 23 x 14 = 322 is the highest number.

Rajesh Reddy said:   9 years ago
@Ramesh.

We know that all the factors of the number A are also the factors of all the multiples of the number A.
In the given problem, 13 and 14 are factors of the Least Common Multiple of 2 numbers, therefore 13 and 14 are also considered as factors of the two numbers.
The HCF of 2 numbers = 23.
Therefore the required numbers are 23 x 13 = 299 and 23 x 14 = 322.
Therefore 23x14=322 is the highest number.
HCF of 299 and 322 = 23,
LCM of 299 and 322 = 4186.
13 and 14 are the factors of 4186.

Palanivel said:   9 years ago
In my view, x and why are given two numbers.

Hcf of (x, y) =23;.
Lcm of (x, y) =13, 14;.

We know that;

Hcf x lcm=X x Y.
So, 23x13=299;.

23 x 14 =322 which is larger so 322 is the answer.

If any mistakes correct me.

Vicky patil said:   8 years ago
Thanks @Vijay Pandey.

N karthik said:   8 years ago
HCF * LCM
X * Y=. 23 * 13 =299.
X * Y= 23 * 14 =322 large.

Falak.. said:   8 years ago
Simple and easy method to understand the solution. Thanks @Sanjeev Goel.

Md Aquib Ansari ho said:   8 years ago
Thanks @Sameera.

Suraj & shani chouhan said:   8 years ago
Thanks for the given solution @Chiya.

Shahriar said:   8 years ago
Let, A and B are the two numbers.

As 23 is the HCF of the two numbers.
We can assume that
a= 23*x, b=23*y, where x and y are the other factors of the numbers.
Now, LCM of a(23*x) and b(23*y) = 23*x*y.
It is given that the other factors of the l.c.m are 13 & 14.
So we can say that x= 13 and y = 14.

Therefore a = 23 * 13,
And b = 23 * 14.
So the larger number is 23*14 = 322.


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