Find the 20th term of the AP whose 7th term is 24 less than the 11th term, first term being 12.

Let the a be first term and d be common difference

As we know

a_n = a + (n - 1)d

Given,

a₇ = a₁₁ - 24

a + 6d = a + 10d - 24

10d - 6d = 24

4d = 24

d = 6

given a = 12

then, a₂₀ = a + 19d

a₂₀ = 12 + 19(6)

= 12 + 114

= 126