Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 40)
40.
(12345679 x 72) = ?
Answer: Option
Explanation:
| 12345679 x 72 | = 12345679 x (70 +2) |
| = 12345679 x 70 + 12345679 x 2 | |
| = 864197530 + 24691358 | |
| = 888888888 |
Discussion:
19 comments Page 2 of 2.
Kamalesh said:
5 years ago
Nice, thanks @Anagha.
JAISON said:
8 years ago
12345679 x (70+2).
12345679 x 70 = 864197530,
12345679 x 2 = 24691358,
864197530 + 24691358 = 888888888.
12345679 x 70 = 864197530,
12345679 x 2 = 24691358,
864197530 + 24691358 = 888888888.
K.ARIVU SELVAN said:
9 years ago
12345679 * 72 = 12345679 * (63 + 9)
12345679 * 63 = 777 777 777 (+)
12345679 * 9 = 111 111 111
-------------------
12345679 * 72 = 888 888 888
I hope this will useful.
12345679 * 63 = 777 777 777 (+)
12345679 * 9 = 111 111 111
-------------------
12345679 * 72 = 888 888 888
I hope this will useful.
Anagha said:
10 years ago
= 12345679*8(10-1).
= 8*(123456790-12345679) = 8*(111111111).
= 888888888.
= 8*(123456790-12345679) = 8*(111111111).
= 888888888.
NIKKY said:
10 years ago
What is a thrift number?
Sidra said:
1 decade ago
How many thrift numbers between 14 to -14(both inclusive)?
Priya said:
1 decade ago
@Satheeskumar.D
But how can we multiply this digit sum method by 1*0 or 0 or 9 as like as you mentioned above. That makes little bit tough. How is this? please explain.
But how can we multiply this digit sum method by 1*0 or 0 or 9 as like as you mentioned above. That makes little bit tough. How is this? please explain.
Satheeshkumar. D said:
1 decade ago
We can apply digit sum method:.
In digit sum method 9 and 0 considered the same.
Digit sum of 1234567 = 1 (1+2+3+4+5+6+7).
&.
Digit sum of 72 = 9 or 0 (7+2).
Now multiply this digit sums 1 x 0 = 0 or 9.
So the digit sum of the answer must be 0 or 9.
888888888 gives the answer of 0 or 9.
(8+8+8+8+8+8+8+8+8=72; 7+2=9).
(Tip: Whenever you count digit sum, skip the number 9 as if it is 0, it works and its true).
In digit sum method 9 and 0 considered the same.
Digit sum of 1234567 = 1 (1+2+3+4+5+6+7).
&.
Digit sum of 72 = 9 or 0 (7+2).
Now multiply this digit sums 1 x 0 = 0 or 9.
So the digit sum of the answer must be 0 or 9.
888888888 gives the answer of 0 or 9.
(8+8+8+8+8+8+8+8+8=72; 7+2=9).
(Tip: Whenever you count digit sum, skip the number 9 as if it is 0, it works and its true).
DeEpU said:
1 decade ago
12345679*72=12345679*(80-8)
8*12345679=98765432
987654320
- 98765432
------------
888888888
8*12345679=98765432
987654320
- 98765432
------------
888888888
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