CBSE BOARD X, asked by satyaram3327, 2 months ago

Find theFind the sum of first 11 terms of the AP: 1
15
,
1
12
,
1
10
… … … … … …. sum of first 11 terms of the AP: 1 15 , 1 12 , 1 10 … … … … … ….

Answers

Answered by prathamanil
0

Answer:

a=115

d= -3

S11 = n/2[2a+(n-1)d]

=11/2[2×115+10×-3]

=11/2[230-30]

=11/2×200

=11×100

=1100

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