Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 51)
51.
476 ** 0 is divisible by both 3 and 11. The non-zero digits in the hundred's and ten's places are respectively:
7 and 4
7 and 5
8 and 5
None of these
Answer: Option
Explanation:

Let the given number be 476 xy 0.

Then (4 + 7 + 6 + x + y + 0) = (17 + x + y) must be divisible by 3.

And, (0 + x + 7) - (y + 6 + 4) = (x - y -3) must be either 0 or 11.

x - y - 3 = 0    y = x - 3

(17 + x + y) = (17 + x + x - 3) = (2x + 14)

x= 2 or x = 8.

x = 8 and y = 5.

Discussion:
37 comments Page 3 of 4.

Rahul said:   9 years ago
By solving through divisibility method we can aslo get value X = 5 and Y = 2. Is it correct?

Padman said:   9 years ago
5 and 2 are not there in the answers given. Hence 8 and 5 selected.

Vishnu Priya said:   9 years ago
Please can anyone explain from (0 + x + 7) - (y + 6 + 4) =x - y - 3. Must be either 0 or 11?

Shahid ali said:   8 years ago
Thank you @Tanya.

Pritam Bose said:   8 years ago
Thank you @Tanya Mazumdar.

Rinkal said:   8 years ago
Thanks @Tanya Mazumdar.

Jashim uddin said:   7 years ago
Thanks @Tanya.

Shekhar said:   7 years ago
How can come x=2 or 8?

Please explain.

Raj said:   7 years ago
Divisibility by 3 condition is sum of all the digits are divisible by 3.
Divisibility by 11 condition is diff of sum of odd and even place digits should be equal to zero.

Let the missing digits be x and y.
Then given value becomes 476xy0.
For divisible by 11: (4+6+y)-(7+x+0)=0
=> 10+y=7+x.
=> y = (7-10)+x.
=> y = x-3 ------> (1).

Now for divisibility by 3: 4+6+7+x+y+0 => 17+x+y.
=> 17+x+x-3 => 14+2x should be divisible by 3,
now try substuiting values:
x=1: 16 not div by 3,
x=2: 18 div by 3,
x=3: 20 not div by 3.
.
.
x=5: 24 div by 3.

So for x=2
=> y= -1 which is not valid.
=> for x= 5
=> y=2. then 10+y =7+x
so the answer 2 and 5.
It will work for 8 and 5.

Abin kumar said:   7 years ago
The sum of the numbers should be divisible by 3 in order for the number to be completely divisible by 3.

So 4+7+6+0=17.

Adding the numbers in the options so that the total number is divisible by 3.

17+ 8+5 = 30.
Hence option C is correct.
(1)


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