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SSC CGL 2018 PYQ — Question 100

SSC CGL Tier II Quant - 19/02/2018 • Quantitative Aptitude • Q100

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If N = 1 + 11 + 111 + 1111 + … +111111111, then what is the sum of the digit's of N?

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 45

N =  1 + 11 + 111 + 1111 + … + 111111111

1 + 11 = 12

1 + 11 + 111 = 123

1 + 11 + 111 + 1111 = 1234

N = 123456789

Now, sum of digits of N = 9 × 10/2 = 45