Question

Can somebody please help me with these two problems?

1. What is the sum of the finite arithmetic series? 26 + 29 + 32 + 35 + 38 + 41 + 44
2. What is the sum of the finite arithmetic series? 7.6 + 6.3 + 5 + 3.7 + 2.4 + 1.1 + (–0.2) + (–1.5),

Answer 1

The formula for sum of AP is S = [2a + (n - 1)d]*n/2 where a is first term of series, n is number of terms and d is the difference 1. here a=26, n=7 and d= 29-26=3 so S = [2*26 + (7 - 1)*3]*7/2 S=245 2. here a=7.6, n=8 and d= 6.3-7.6=-1.3 so S = [2*7.6 + (8 - 1)*-1.3]*8/2 S=24.4