Question

The sum of the first and the 20 th terms of an arithmetic sequence is 65
a] what is the sum of the first 20 terms of the sequence

Answer 1

Answer:

650

Step-by-step explanation:

1st term + 20th term = 65

(a) + (a +19d) = 65

2a+19d=65   -------------- 1

Now, sum of first 20 terms

20/10 [2a+19d]

10 [65]  =  650

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