Find the sum of first twenty terms of arithmetic series 2+7+12+...using suitable formula
Answers
Answered by
3
20/2(2×2+(20-1)5)
10(2×2+19*5)
10(4+95)
990
puru43paphyw:
wrong ans.
why it is
because you took n = 12, it should be 20.
ok
Answered by
2
Answer:
920
Step-by-step explanation:
Given:
a= 2 , common difference,d= 7-2=5 , n = 20
so , Sn = n/2[2a+(n-1)d]
S20 = 20/2[2*2+(20-1)5]
= 10[ 4+95]
S20 = 990 (Ans)
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