Question

Which term of the AP 3,8, 13,18,…. Will be 55 more than its 20^th term?

Answer 1

Here, a = 3 and d = (8 - 3) = 5

The 20_th term is given by

T₂₀ = a + (20 - 1) d = a + 19d = 3 + 19 x 5 = 98

∴ Required term = (98 + 55) = 153

Let this be the nth term.

Then T_n = 153

\(\Rightarrow 3+(n\,-\,1)\times5=153\)

\(\Rightarrow\) 5n = 155

\(\Rightarrow\) n = 31

Hence, the 31^st term will be 55 more than 20^th term.