Question

What is the sum of the arithmetic sequence 308, 304, 300, …, if there are 25 terms?

Answer 1

6500

Explanation:

Sum of an arithmetic series = `n/2(2a+(n-1)d)`
where a = first term, n = number of terms, d = common difference

Sum = `25/2(2*308+24*(-4))`
`= 12.5(616-96)`
`=12.5*520`
`=6500`