Question

Find the 12^th term from the end of the AP: –2, –4, –6,..., –100.

Answer 1

Given AP: –2, –4, –6,..., –100

Here, first term (a) = –2,

Common difference (d) = –4 – (–2) = –2

And the last term (l) = –100

We know that, the n^th term of an AP from the end is a_n = l – (n – 1)d,

Where l is the last term and d is the common difference.

∴ 12^th term from the end,

a₁₂ = –100 – (12 – 1)(–2)

= –100 + (11)(2)

= –100 + 22

= –78

Hence, the 12^th term from the end is –78.