Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 16)
16.
If the number 517*324 is completely divisible by 3, then the smallest whole number in the place of * will be:
Answer: Option
Explanation:
Sum of digits = (5 + 1 + 7 + x + 3 + 2 + 4) = (22 + x), which must be divisible by 3.
x = 2.
Discussion:
52 comments Page 4 of 6.
Pooja said:
9 years ago
It's quite simple. Consider * as x and add all the numbers which will become (22+x). Now choose the number from options one by one and put in place of x and then try to divide it by 3. As I put the first option in place of x = (22+2) = 24 which is divided by 3.
Shiva said:
10 years ago
5 + 1 + 7 + x + 3 + 2 + 4 = 22.
22 + 3 - x = 24.
24/12 = 2.
22 + 3 - x = 24.
24/12 = 2.
Ramesh nigam said:
10 years ago
Can we apply this trick on all numbers, or its just applicable on number 3?
Shailu said:
1 decade ago
Just all see @Nikitha comment she describes it well.
Nithya said:
1 decade ago
517*324 its divided by 3.
5+1+7+X+3+2+4 = 22+X.
X = 0, 1, 2, 3, .
22+0 = 22. Its not divided by three.
22+1 = 23. Its not divided by three.
22+2 = 24(8*3) = 24 is divided by three.
So, the x value is 2. The two will be added. So the number is divided by three. So the answer is three.
5+1+7+X+3+2+4 = 22+X.
X = 0, 1, 2, 3, .
22+0 = 22. Its not divided by three.
22+1 = 23. Its not divided by three.
22+2 = 24(8*3) = 24 is divided by three.
So, the x value is 2. The two will be added. So the number is divided by three. So the answer is three.
Sudharshan said:
1 decade ago
Can you send anybody divisible rules for remaining numbers 7, 6, 8?
Prajith said:
1 decade ago
Is this method is only applicable when the divisor is 3?
Krish said:
1 decade ago
We can't understand clearly give me a correct notes.
Vidyadhar said:
1 decade ago
(5 + 1 + 7 + x + 3 + 2 + 4)
=22+x means
22/3 Remain 1
Then
3-1 = 2
Answer is 2
=22+x means
22/3 Remain 1
Then
3-1 = 2
Answer is 2
Pavan said:
1 decade ago
@Ram, Sonakshi.
The adding of digits to check divisibility can be done only for 3 which is rule for test of divisibility for 3.
Similarly,To check divisibility of 9 the sum of digits should be 9.
Ex: 45 => 4+5=9 . So 45 is divisible by 9.
Each digit has its own Divisibility rule to check whether it exactly divides the given or not.
The adding of digits to check divisibility can be done only for 3 which is rule for test of divisibility for 3.
Similarly,To check divisibility of 9 the sum of digits should be 9.
Ex: 45 => 4+5=9 . So 45 is divisible by 9.
Each digit has its own Divisibility rule to check whether it exactly divides the given or not.
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