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sachin_yadav
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If the sum of the first k positive integers is equal to, k(k+1)/2, What is the sum of the integers from n to m, inclusive, where 0<n<m?
A. (m(m+1)-(n-1)n)/2
B. (m(m+1)-(n+1)n)/2
C. (m(m-1)-(n-1)n)/2
D. (m(m-1)-(n+1)n)/2
E. (m(m+1)-(n-1)n)/4
OA is A
Why OA cannot be B
Suppose i need the sum of integers from 10 to 20. I will calculate the sum of (1 to 10) and subtract it from (1 to 20)
(sum of 1 to 20) - (sum of 1 to 10) = (sum of 10 to 20)
(m(m+1)-(n+1)n)/2 (where i am wrong)
A. (m(m+1)-(n-1)n)/2
B. (m(m+1)-(n+1)n)/2
C. (m(m-1)-(n-1)n)/2
D. (m(m-1)-(n+1)n)/2
E. (m(m+1)-(n-1)n)/4
OA is A
Why OA cannot be B
Suppose i need the sum of integers from 10 to 20. I will calculate the sum of (1 to 10) and subtract it from (1 to 20)
(sum of 1 to 20) - (sum of 1 to 10) = (sum of 10 to 20)
(m(m+1)-(n+1)n)/2 (where i am wrong)
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