Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 34)
34.
How many of the following numbers are divisible by 3 but not by 9 ?
2133, 2343, 3474, 4131, 5286, 5340, 6336, 7347, 8115, 9276
5
6
7
None of these
Answer: Option
Explanation:

Marking (/) those which are are divisible by 3 by not by 9 and the others by (X), by taking the sum of digits, we get:s

2133 9 (X)

2343 12 (/)

3474 18 (X)

4131 9 (X)

5286 21 (/)

5340 12 (/)

6336 18 (X)

7347 21 (/)

8115 15 (/)

9276 24 (/)

Required number of numbers = 6.

Discussion:
12 comments Page 1 of 2.

Mr.Prakash said:   3 years ago
Thank you very much @Ram,

Very helpful solution.

Roobi said:   3 years ago
@Ajax.

It's quite easy to understand. Thanks.
(1)

Chintu said:   4 years ago
Thank you soo much @Ajax.

It is very simply to understand.

Ujjwal said:   6 years ago
A number divisible by 9 must be divisible by 3.

Anomis said:   6 years ago
5340 is not divisible by 9.

So, the answer is (A).

Ram said:   7 years ago
A number divisible by 9- sum of all those digits should be divisible by 9.

Reshmaa said:   8 years ago
In shortcut, how to check whether a number is divisible by 9 and not by 3?

Aishu said:   9 years ago
Shortcut method:

To check a number divisible by 9- sum of all those digits should be divisible by 9.

Just add all those digits in each no and check if /9.

Ajax said:   9 years ago
Simple sum of the number, if sum is only divide by 3 so that answer like.

(2+1+3+3) = 9 is divide by both 3 and 9.

(2+3+4+3) = 12 is only divide by 3.

Check all.
(2)

Manish said:   10 years ago
Sir please give us a short-cut method for doing this question.


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