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Which term of the A.P. 3, 15, 27, 39,.. will be 132 more than its 54th term?
Arithmetic Progressions
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31/05/2021 11:37 am
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Which term of the A.P. 3, 15, 27, 39,.. will be 132 more than its 54th term?
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31/05/2021 11:38 am
Given A.P. is 3, 15, 27, 39, …
first term, a = 3
common difference, d = a2 − a1
= 15 − 3 = 12
We know that,
an = a+(n−1)d
a54 = a+(54−1)d
= 3 + (53)(12)
⇒ 3 + 636 = 639
a54 = 639
We have to find the term of this A.P. which is 132 more than a54, i.e.771.
Let nth term be 771.
an = a+(n−1)d
771 = 3+(n −1)12
768 = (n−1)12
(n −1) = 64
n = 65
Therefore, 65th term was 132 more than 54th term.
Or another method is;
Let nth term be 132 more than 54th term.
n = 54 + 132/2
= 54 + 11 = 65th term
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