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Which one of the following is a factor of the sum of first twenty-five natural numbers ?
Answer & Solution
Correct Answer:
Option
C
Sum first n natural numbers
$${\text{ = }}\left[ {\frac{{{\text{n(n + 1)}}}}{2}} \right] = 25 \times 13$$
Sum of first 25 natural numbers
$${\text{ = }}\frac{{25(26)}}{2} = 25 \times 13$$
Now check option
Clearly, we can see 13 is factor
So, '13' is answer
$${\text{ = }}\left[ {\frac{{{\text{n(n + 1)}}}}{2}} \right] = 25 \times 13$$
Sum of first 25 natural numbers
$${\text{ = }}\frac{{25(26)}}{2} = 25 \times 13$$
Now check option
Clearly, we can see 13 is factor
So, '13' is answer
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