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An AP consists of 23 terms. If the sum o...

An `AP` consists of `23` terms. If the sum of the three terms of in the middle is `141` and the sum of the last three terms is `261`, then the first term is

A

`6`

B

`5`

C

`4`

D

`3`

Text Solution

Verified by Experts

The correct Answer is:
D
`t_(11) + t_(12) + t_(13) = 141`
and `t_(21) + t_(22) + t_(23) = 261`
`:. 3a + 33d = 141 rArr a + 11d = 47`
and `3a + 63d = 261 rArr a + 21d = 87`
On solving eqs. `(i)` and `(ii)`, we get
`a = 3, d = 4`.
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