Question

10.
The sum of the series 9,5, 1, .........to 100 terms is :​

Answer 1

Answer:

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Answer 2

a=9. d=9-5=4. n=100

Sn= n/2(2a+(n-1)d)

Sn=100/2(2*9+(100-1)4)

S 100=50(18+(99)4)

S100=50(18+396)

S100=50(424)

S 100=21200