SOLUTION: In an AP the first term is 4 and the nth term is 36. Given that the sum of the first n terms is 363, find n and the common difference of the AP.

SOLUTION: In an AP the first term is 4 and the nth term is 36. Given that the sum of the first n terms is 363, find n and the common difference of the AP.

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Question 888397: In an AP the first term is 4 and the nth term is 36. Given that the sum of the first n terms is
363, find n and the common difference of the AP.

Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
S = �(a + an)n
363 = �(4 + 36)n
363 = �(40)n
363 = 20n
363/20=n
n=18.15 which is not possible
n must be a positive integer

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