Question

The 11th term of the A.P. `-5, -5/2, 0, 5/2,` ...... is ______.

Answer 1

The 11th term of the A.P. `-5, -5/2, 0, 5/2,` ...... is 20.

Explanation:

First term a₁ = –5. 

Common difference `d = (-5/2) - (-5) = 5/2`. 

Use the nth-term formula T_n = a + (n – 1)d.

So `T_11 = -5 + (11 - 1)(5/2)` 

= `-5 + 10(5/2)`

= –5 + 25 

= 20