Question

What is the sum of following series if, the number of terms is 115
6 + (-8) + 9 + (-10) + 11 + (-12) + ...... = ?​

Answer 1

Answer:

63

excluding 6 the terms will be 114.

if we notice after the first term the sum of two consecutive terms is +1

also their are 114 terms

now every two terms yield 1

114/2=57

57times one will come+ the first term 6

so total sum will be 63