Question

The 18th term of an A.P is 256 and the common difference is 4. Find 3rd term.​

Answer 1

$we \: know \: that \\ where\\ a _{n} = a_{1} + (n - 1)d \\ a _{n} = nth \: term \: of \: \bold{ap} \\ a _{1} = first \: term \\ d = commo n \: difference$

$n = 18 \\ a _{18} = a _{1} + (18 - 1) \times 4 \\ 256= a _{1} + 17 \times 4 \\ a _{1} = 256 - 68 = 188 \\ \\ if \: n = 3 \\ a _{3} = a _{1} + (3 - 1) \times 4 \\ a _{3} = 188 + 8 = 196$