find the sum of the ap 1 by 15, 1 by 12 , 1 by 10 ..... to 11 terms
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Answer:
S11 = 33/20
Step-by-step explanation:
AP: 1/15, 1/12, 1/10, ...
Therefore, a=1/15
d=1/12-1/15
=5/60-4/60 [ Taking LCM ]
=1/60
We know that, Sn = n/2 [2a + (n-1)d]
Therefore, S11 = 11/2 [2(1/15) + (11-1)1/60]
S11 = 11/2 [2/15 + 10(1/60)]
S11 = 11/2 [2/15 + 1/6]
S11 = 11/2 [4/30 + 5/30]
S11=11/2 [9/30]
S11 = 99/60
S11 = 33/20
Therefore, sum of 11 terms of the AP: 1/15, 1/12, 1/10, ... is 33/20.
I hope you got your answer.
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