# In an A.P., 1^(st) terms is 1 and the last term is 20. The sum of all terms is 399 then n = …………. A)42 B)38 C)21 D)19

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In an A.P., 1^(st) terms is 1 and the last term is 20. The sum of all terms is 399 then n = …………. A)42 B)38 C)21 D)19
A. 42
B. 38
C. 21
D. 19

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