Question

11, 8, 5, 2,
In this A.P. which term is number - 151 ?​

Answer 1

Solution :-

• In the given Arithmetic Progression we can see that the first term a1 = 11 and common difference (d) = -3

• Consider the term -151 to be the last term of the Ap and take it as l or an .

Formula Used :-

$\sf{ \bold{ \boxed{ \purple{an = (a + n - 1)d}{} }{} }{} }{}$

$\sf{ - 151 = 11 + (n - 1) \times - 3}{} \\ -162 = (n - 1) \times - 3 \\ (n - 1) = - \frac{ - 162}{ - 3} \\ n - 1 = 54 \\ hence \: n = 54 + 1 = 55$

• Hence -151 is a term of the Ap 11 8 5 2