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The sum of all the 2-digit numbers is :
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- 4995
- 4950
- 4945
- 4905
Correct Option: D
The two-digit numbers are : 10, 11, 12, ..... 97, 98, 99.
As we know that,
| Sum of N natural Numbers 1 + 2 + 3 ........ + n = | |
| 2 |
As we know from the given question,
Required sum = 10 + 11 + 12 + .......... + 99
We can write as below,
∴ Required sum = ( 1 + 2 + 3 +......+ 99 ) – ( 1 + 2 + ..... + 9 )
| ∴ Required sum = | − | ||
| 2 | 2 |
∴ Required sum = 4950 – 45 = 4905
