Question

Find the sum of arithmetic progression
8, 3, -2.... Upto 22 terms

Answer 1

Hey !

8 , 3 , -2....

$a = 8 \\ \\ d = 3 - 8 = - 5 \\ \\ n = 22 \\ \\ sn = \frac{n}{2} \times (2a + (n - 1)d) \\ \\ sn = \frac{22}{2} \times (2 \times 8 + (22 - 1) \times - 5) \\ \\ sn = 11 \times (16 + (11) \times - 5) \\ \\ sn = 11 \times (16 - 55) \\ \\ sn = 11 \times - 39 \\ \\sn = - 429$

The sum of this arithmetic progression upto 22 terms is -429.

Hope it is satisfactory :-)

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Answer 2

the ans of this question is 45.5