SOLUTION: Find the sum of 1st 12 term of the series 3,7,11,15,19

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Question 862763: Find the sum of 1st 12 term of the series 3,7,11,15,19
Answer by mananth(16946) About Me  (Show Source):
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3,7,11,15
is an Arithmetic sequence
a=3 and d=4
n=12
Sn= n/2[2a+(n-1)d]
S12 =12/2[2*3+(12-1)*4]
=6[6+44]
=6*50
=300
S12 = 300