Question

The first term of an arthemetic progression is -5 and last term is 45 If thesum of the terms is 120 the find the number of terms

Answer 1

Hey friend, Here is your answer-

t1 = -5 , tn = 45 , Sn = 120

Sn = n/2 (t1 + tn ).......... (formula)

120 = n/2 ( -5 + 45)

240 = 40n

n = 240 / 40

n = 6

Therefore the number of terms is 6.

Hope it will help you.

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Answer 2

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