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. 14)
14.
The least number which when divided by 5, 6 , 7 and 8 leaves a remainder 3, but when divided by 9 leaves no remainder, is:
1677
1683
2523
3363
Answer: Option
Explanation:

L.C.M. of 5, 6, 7, 8 = 840.

Required number is of the form 840k + 3

Least value of k for which (840k + 3) is divisible by 9 is k = 2.

Required number = (840 x 2 + 3) = 1683.

Discussion:
86 comments Page 5 of 9.

Tg said:   7 years ago
2 has come because 5*6*7*8 is 1683.

Ram said:   7 years ago
Thanks for the explanation @Suchita.

Renu said:   7 years ago
Good explanation, Thanks @Suchita.

Munna Mudassir said:   8 years ago
Another shortcut which will work in this case is checking thew divisibility by 9.
only 1683 is divisible by 9 hence the answer is 1683. In case there is more numbers divisible by you have to check it as my previous answer.

Saurabh agrawal said:   1 decade ago
Suchita's trick is great. Very short and productive.

Lali said:   1 decade ago
It clear when we put a value of k 1 then 5,6,7,8, leave the remainder 3 and 6 in case of 9. when k=2. in this case no remainder is left.

Chandresh said:   1 decade ago
But concept of finding the value of k is still not clear.

Can anyone tell the concept except logical solution?

Satheesh said:   1 decade ago
Divide each answer by 9 which one has no reminder that's answer.

Feroz said:   1 decade ago
we get LCM =840 since 843 is divided by 3
when we divide it by 9 it leaves a remainder of 6
since we need a least no. divided by three which also leaves 3 remainder
we put value of k=1, 2, 3.... till we get the required no.
since

Pankaj said:   1 decade ago
Nice Suchita.


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