Solution: 

Given that,

a₆ = 19 and a₁₇ = 41

As we know that, to find nth term in an A.P = a + (n – 1)d

therefore,

a₆ = a + (6-1)d

= a + 5d = 19 ——-(i)

Similarly,

a₁₇ = a + (17 – 1)d

= a + 16d = 41 ———-(ii)

Solving (i) and (ii),

(ii) – (i)

a + 16d – (a + 5d) = 41 – 19

11d = 22

d = 2

Using d in eqn(i), we get

a + 5(2) = 19

a = 19 – 10 = 9

Now, the 40th term is given by a40 = 9 + (40 – 1)2 = 9 + 78 = 87

Hence the 40th term is 87.