The first term of ap is 5 the last term is 45 and the sum is 400 find

1.	The first term of ap is 5 the last term is 45 and the sum is 400 find number of terms
Answer» S = N / 2 ( A + L ) .....400= N / 2 ( 5 + 45 ) = 400 = N/ 2 ( 50 ) 400 = 25n .....N = 16 16

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