Q15 of 176 Page 8

The 8th term of an A.P. is 37, and its 12th term is 57. Find the A.P.

We have

a₈ = a + (8 – 1)d = a + 7d = 37 …(1)

and a₁₂ = a + (12 – 1)d = a + 11d = 57 …(2)

Solving the pair of linear equations (1) and (2), we get

a + 7d – a – 11d = 37 – 57

⇒ – 4d = –20

⇒ d = 5

Putting the value of d in eq (1), we get

a + 7(5) = 37

⇒ a + 35 = 37

⇒ a = 2

Hence, the required AP is 2, 7, 12, 17,…

The 7th term of an A.P. is 20 and its 13th term is 32. Find the A.P. [CBSE 20041

The 7th term of an A.P. is – 4 and its 13th term is – 16. Find the A.P. [CBSE 20041

Find the 10th term of the A.P. whose 7th and 12th terms are 34 and 64 respectively.

For what value of n are the nth term of the following two A.P's the same. Also find this term

13, 19, 25, ... and 69, 68, 67, ...