Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 3)
3.
The least perfect square, which is divisible by each of 21, 36 and 66 is:
Answer: Option
Explanation:
L.C.M. of 21, 36, 66 = 2772.
Now, 2772 = 2 x 2 x 3 x 3 x 7 x 11
To make it a perfect square, it must be multiplied by 7 x 11.
So, required number = 22 x 32 x 72 x 112 = 213444
Discussion:
80 comments Page 4 of 8.
K.viji said:
9 years ago
Why multiplied by 7x11?
Neelraj said:
9 years ago
It is multiplied by 7 so that we get 7^2 and 11 because we get 11^2. So perfect square is obtained.
Logapriya said:
9 years ago
Please anyone explain in simple way.
Najeeb said:
9 years ago
How to find out least perfect square?
Nick said:
9 years ago
How to find out LCM? Someone help me.
Aadal said:
8 years ago
Hi, @Nick! this is the way to take out lcm.
Suppose the number is 27 now,
27will not go with 2 but with 3 so we'll divide it with 3 as follow.
3/27
3/9
3/3
=1
So lcm =3*3*3.
So, in nutshell, we have to take a least no divisible by the given no and then whatever the quotient comes write it in the next line and then again divide that no divisible by least no and then the process continues until you get 1 at last keep solving and in the end write all the multiples together.
Suppose the number is 27 now,
27will not go with 2 but with 3 so we'll divide it with 3 as follow.
3/27
3/9
3/3
=1
So lcm =3*3*3.
So, in nutshell, we have to take a least no divisible by the given no and then whatever the quotient comes write it in the next line and then again divide that no divisible by least no and then the process continues until you get 1 at last keep solving and in the end write all the multiples together.
Shudhakar kumar gupta said:
8 years ago
7and 11 multiply because according to question make perfect square 2 and 3 is left square but 7 and 11 not a perfect square so 7and 11 make a perfect square so multiply 7 and 11.
Anomi said:
8 years ago
21 is having a factor as 7 and 3.
So check each option whether it is divisible by 7 or not.
So option a is only divisible by 7.
So check each option whether it is divisible by 7 or not.
So option a is only divisible by 7.
Rashmi said:
6 years ago
Please explain the second step.
Ram said:
2 weeks ago
Understandable explanations. Thanks all.
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