Which term of the AP : 3, 15, 27, 39, . . . will be 132 more than its 54th term?
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Answered by
10
Answer:
AP - 3, 15, 27, 39...........
a = 3
d = 15-3 = 12
54th term = t54 = a + 53d
=> 3 + 53(12)
=> 3+ 636
=> 639
132 more than 54th term = 132 + 639 = 771
=> an = a + (n-1)d
=> 771 = 3 + (n-1)12
=> 771 - 3 = 12n - 12
=> 768 + 12 = 12n
=> 780/12 = n
=> n = 65
therefore the term which is 132 more than 54th term is 65th term
i think this is the answer...........I hope this helps u
Answered by
7
Assume,
First term be a
Common difference be d
Here,
a = 3,
d = 15 - 3 = 12
n = 54
Using Formula :-
a(n) = a + (n - 1)d
a(54) = 3 + (54 - 1) × 12
a(54) = 3 + 53 × 12
a(54) = 3 + 636
a(54) = 639
Now,
132 more than its 54th term :-
= 132 + 639
= 771
Now,
a(n) = a + (n - 1)d
a + (n - 1)d = 771
3 + (n - 1)12 = 771
3 + 12n - 12 = 771
12n = 771 + 12 - 3
12n = 780
n = 780/12
n = 65
Therefore,
We get,
65th term is 132 more than 54th term
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