Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 15)
15.
72519 x 9999 = ?
Answer: Option
Explanation:
| 72519 x 9999 | = 72519 x (10000 - 1) |
| = 72519 x 10000 - 72519 x 1 | |
| = 725190000 - 72519 | |
| = 725117481. |
Discussion:
16 comments Page 1 of 2.
Abid said:
5 days ago
It is much easier if we find the sum of the digits. Only opt A's Digits' sum is divisible by 9.
So, that's the answer.
So, that's the answer.
Anurag said:
3 years ago
@All.
The best short trick to multiply any digit with 99,999,999,99999999,..
Example;
33 * 99 = 33 -1 || 9-3 || 10-3 => 3267.
237 * 999 = 237-1 || 9-2 || 9-3 || 10 - 7 (10 - last digit) => 236763.
The best short trick to multiply any digit with 99,999,999,99999999,..
Example;
33 * 99 = 33 -1 || 9-3 || 10-3 => 3267.
237 * 999 = 237-1 || 9-2 || 9-3 || 10 - 7 (10 - last digit) => 236763.
(2)
Manoj said:
4 years ago
From where do we get 5x?
(2)
Aashu said:
5 years ago
7 + 2 + 5 + 1 + 9 = 24 again 2 + 4=6
9 + 9 + 9 + 9 = 36 again 3 + 6 =9
Given =72519 * 9999 = 9 * 6 = 54 sum of 5 + 4= 9
Now find the sum of the digits in the given option
A)7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 9,
Similarly for
B)4
C)5
D)8
So, option A is the correct answer. Hope my answer is useful.
9 + 9 + 9 + 9 = 36 again 3 + 6 =9
Given =72519 * 9999 = 9 * 6 = 54 sum of 5 + 4= 9
Now find the sum of the digits in the given option
A)7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 9,
Similarly for
B)4
C)5
D)8
So, option A is the correct answer. Hope my answer is useful.
(17)
Mustafa said:
7 years ago
This trick always works if m * n when the numbers in m > n and n = any number of 9's sequence.
1) Count number of 9's in n.
2) Add those many 0's in the m number.
3) Subtract the original number.
eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.
1) Count number of 9's in n.
2) Add those many 0's in the m number.
3) Subtract the original number.
eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.
(1)
Mustafa said:
7 years ago
It works if m * n when the numbers in m > n and n = any number of 9's sequence.
1) count number of 9's in n.
2) add those many 0's in the m number.
3) subtract the original number.
eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.
1) count number of 9's in n.
2) add those many 0's in the m number.
3) subtract the original number.
eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.
(1)
Smit said:
8 years ago
If we multiply all then option C is correct.
Vamsi aripaka said:
8 years ago
Thank for explaining the solution.
(1)
Roshan said:
9 years ago
I think it's 72446481.
Is it correct?
Is it correct?
(3)
Krishnamurthy said:
9 years ago
The easiest method can be:
72519 x 9999.
If the multiplier is series of 9 (i. e. 9, 99, 999. ) then,
Add every digit in the given answer (i.e. 7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 36, add the answer again, i.e. 3 + 6 = 9).
And if the final answer is 9 then that number itself answers.
72519 x 9999.
If the multiplier is series of 9 (i. e. 9, 99, 999. ) then,
Add every digit in the given answer (i.e. 7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 36, add the answer again, i.e. 3 + 6 = 9).
And if the final answer is 9 then that number itself answers.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers