Question

which term of the AP.​

Answer 1

here is your answer.

Answer 2

a = 3

d = 12

54nd term = a + (n-1) d

                  = 3 + (54 - 1) 12

                  = 3 + 53 × 12

                  = 3 + 636

                   = 639

According to question,

639 + 132 = 771 = required term

771 = a + (n-1) d

771 = 3 + (n-1) 12

768 = (n-1) 12

768/12 = n-1

64 = n-1

∴ required term, 'n' = 64 + 1 = 65th term