in an A.P the first term is -5 and last term is 45 . if sum of all number in the A. P is 120 , then how many terms are there in A.P
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in an A.P the first term is -5 and last term is 45 . if sum of all number in the A. P is 120 , then how many terms are there in A.P
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Step-by-step explanation:
S=n/2 (a+l) where a is the first term,
l is the last term
s is the sum of A. P
n= no of terms
120 =n/2(-5+45)
240=40n
n=6