Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 97)
97.
If x and y are positive integers such that (3x + 7y) is a multiple of 11, then which of the following will be divisible by 11 ?
4x + 6y
x + y + 4
9x + 4y
4x - 9y
Answer: Option
Explanation:

By hit and trial, we put x = 5 and y = 1 so that (3x + 7y) = (3 x 5 + 7 x 1) = 22, which is divisible by 11.

(4x + 6y) = ( 4 x 5 + 6 x 1) = 26, which is not divisible by 11;

(x + y + 4 ) = (5 + 1 + 4) = 10, which is not divisible by 11;

(9x + 4y) = (9 x 5 + 4 x 1) = 49, which is not divisible by 11;

(4x - 9y) = (4 x 5 - 9 x 1) = 11, which is divisible by 11.

Discussion:
23 comments Page 1 of 3.

Siddhartha Chakraborty said:   2 years ago
x = 4 and y = 3.
Then x+y+4 = 4+3+4 = 11(which is divisible by 11 )
Hence, I think option B is also correct.
(19)

Vishwas said:   2 years ago
x = 4 and y = 3.
and x+y+4 = 4+3+4 = 11(which is divisible by 11 )
Hence, I think option B is also correct.
(7)

Priya said:   1 year ago
Why do we put x=5, y=1?

Anyone, please explain me.
(4)

Parvez said:   2 years ago
Here, x=4 and y=3 is also correct.
(4)

Arpit saxena said:   4 years ago
We know that the numbers divisible/multiple by 11s are 11, 22, 33, 44, 55.

So on.

Except for the number 11 which can not be made by using the expression (3x+7y) so we find the other numbers which are least and divisible by 11. Which number could be 22.

So we find the numbers that make 22 which are x=5, y=1. After putting these values in expression we can find 22.

Similarly;

These values can determine which given expression is divisible by 11.
(1)

Krishna Thakur said:   4 years ago
@Aall.


If we put x =11 and y =11 then the equation will be;

3*11+7*11= 110, which is also a multiple of 11. And after applying these values to option (a) 4x + 6y this option is also correct.

4*11+6*11 = 110, which is also divisible by 11.

Please correct me, If I am wrong.
(1)

Techno said:   8 years ago
What a joke, keep hitting during the exams.

Prakash said:   5 years ago
As x=4 and y=3 is required. So, x+y+4 is the correct answer.

Prakash said:   5 years ago
As x=4 and y=3 is required.
So, x + y + 4 is correct answer.

Angel said:   5 years ago
But if I take x as 3 and why as 7 it does satisfy the condition of being divisible by 11 and the correct option is A right?


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