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The sum 2xx5+5xx9+8xx13+…10 terms is...

The sum `2xx5+5xx9+8xx13+…10` terms is

A

`4500`

B

`4555`

C

`5454`

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
B
`(b)` `S=2xx5+5xx9+8xx13+…10`terms
`t_(r )=(3r-1)(4r+1)`
`=12r^(2)-r-1`
`:.S=sum_(r=1)^(10)(12r^(2)-r-1)`
`=12(10.11.21)/(6)-(10.11)/(2)-10`
`=10(462-(11)/(2)-1)`
`=4555`
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