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. 11)
11.
Find the lowest common multiple of 24, 36 and 40.
Answer: Option
Explanation:
2 | 24 - 36 - 40
--------------------
2 | 12 - 18 - 20
--------------------
2 | 6 - 9 - 10
-------------------
3 | 3 - 9 - 5
-------------------
| 1 - 3 - 5
L.C.M. = 2 x 2 x 2 x 3 x 3 x 5 = 360.
Discussion:
21 comments Page 1 of 3.
Simbu said:
1 decade ago
How to solve it?
Raviteja said:
1 decade ago
24=2*2*2*3=(2^3 * 3^1).
36=2*2*2*3*3=(2^3 * 3^2).
40=2*2*2*3*5=(2^3 * 3^1 * 5^1).
For L.C.M take largest power primes
L.C.M=2^3 * 3^2 * 5^1=2*2*2*3*3*5=360.
36=2*2*2*3*3=(2^3 * 3^2).
40=2*2*2*3*5=(2^3 * 3^1 * 5^1).
For L.C.M take largest power primes
L.C.M=2^3 * 3^2 * 5^1=2*2*2*3*3*5=360.
Girika said:
1 decade ago
This is wrong. LCM of 24, 36, 40 is 720.
Mahesh said:
1 decade ago
4|24 36 40
3|6 9 10
2|2 3 10
3|1 3 5
5|1 1 5
|1 1 1
4*3*2*3*5 = 360.
3|6 9 10
2|2 3 10
3|1 3 5
5|1 1 5
|1 1 1
4*3*2*3*5 = 360.
(1)
Keerthi said:
1 decade ago
LCM is 720 How do you get 360?
Jeevan said:
1 decade ago
24=2*2*2*3 ///24=2*3*4 not possible **use small numbers **.
36=2*2*3*3.
40=2*2*2*5.
Now take common from combination of 3 numbers i.e 2,2.
Now take common from combination of 2 numbers i.e 2,3.
Now use numbers which do not have pair i.e 3,5.
Now multiply 2*2*2*3*3*5=360.
Ans is 360.
36=2*2*3*3.
40=2*2*2*5.
Now take common from combination of 3 numbers i.e 2,2.
Now take common from combination of 2 numbers i.e 2,3.
Now use numbers which do not have pair i.e 3,5.
Now multiply 2*2*2*3*3*5=360.
Ans is 360.
Janu said:
1 decade ago
Is there any shortcut method for 3 digits number.
Sakshi said:
1 decade ago
We generally break the numbers into prime numbers.
So if 24 = 2*12 = 2*(3*4) = 2*3*2*2 = 2^3*3.
Follow this for the other numbers too. This is the shortcut and safest method.
So if 24 = 2*12 = 2*(3*4) = 2*3*2*2 = 2^3*3.
Follow this for the other numbers too. This is the shortcut and safest method.
Mahesh said:
1 decade ago
If we do the LCM process with 6, 4, 2 as divisors we are getting the LCM as 720 and with the numbers 2, 2, 3, 2 as divisors we are getting 360 as LCM.
Why that difference is occurring and which one we should consider as LCM?
Why that difference is occurring and which one we should consider as LCM?
Sudheer said:
10 years ago
@Keerthi @Girika.
The LCM of 24, 36, 40 is 360 only, not 720. Once check it.
The LCM of 24, 36, 40 is 360 only, not 720. Once check it.
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