Q13 of 55 Page 1

Which term of the A.P. 3, 14, 25, 36, …., will be 99 more than its 25th term?

In the given AP, the first term = a = 3

Common difference = d = 14 – 3 = 11


To find: place of the term which is 99 more than its 25th term.


So, we first find its 25th term.


Since, we know that


an = a + (n-1) × d


a25 = 3 + (25 -1) × 11


a25 = 3 + 24 × 11


a25 = 3 + 264


a25 = 267


25th term of the AP is 267.


Now, 99 more than 25th term of the AP is 99 + 267 = 366.


So, to find: place of the term 366.


So, let an = 366


Since, we know that


an = a + (n-1) × d


366 = 3 + (n -1) × 11


366 – 3 = 11n - 11


363 = 11n - 11


363 + 11 = 11n


11n = 374


n = 374/11 = 34


34th term of the AP is the term which is 99 more than 25th term.


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