1.

Which term of the AP 3, 15, 27, 34, ……. will be 132 more than its 54th term?

Answer»

Given,

AP is 3, 15, 27, 34, ……. 

First term of AP is a = 3 and common difference of AP is d = a2 – a1 

= 15 – 3 

= 12. 

54th term of AP is a54 = a + (54 – 1)d 

(∵ an = a + (n – 1) d and n = 54) 

= 3 + 53 × 12 

= 3 + 636 

= 639. 

(∵ a = 3 & d = 12) 

Let nth term of AP is 132 more than its 54th term. 

i.e.,

an = 132 + a54 

= 132 + 639 = 771 

⇒ 3 + (n – 1) 12 = 771 

(∵ a = 3 & d = 12 and an = a + (n – 1) d)

⇒ 12(n − 1) = 771 − 3 = 768 

⇒ n − 1 = \(\frac{768 }{12}\) = 64 

⇒ n = 64 + 1 = 65.

Hence,

65th term of AP is 132 more than its 54th term.

Given a = 3, d = 12, n = 54.
We know that an=a+(n-1) * d   ---------- (1)

                           = 3 + (54-1) * 12
                           = 3 + 53 * 12
                          =639

                  a54 = 639.
 

Given that the term is 132 more than its 54th term = 639 + 132 = 771.
on substituting in (1), we get

771 = 3 + (n-1) * 12
768 = (n-1) * 12
768/12 = n-1
n-1 = 64
n = 65.
 

Therefore the 65th term is 132 more than its 54th term.Given a = 3, d = 12, n = 54.

We know that an=a+(n-1) * d   ---------- (1)

                            = 3 + (54-1) * 12

                            = 3 + 53 * 12

                            = 639.

                     a54 = 639.
 

Given that the term is 132 more than its 54th term = 639 + 132 = 771.

on substituting in (1), we get

771 = 3 + (n-1) * 12

768 = (n-1) * 12

768/12 = n-1

n-1 = 64

n = 65.

Therefore the 65th term is 132 more than its 54th term.



Discussion

No Comment Found

Related InterviewSolutions