Question

Which term of the Arithmetic Progression -7,-12,-17,-22.. Will be 82?

Answer 1

$\huge\bold{Answer:-}$

Given :- The Ap is -7 , -12, -17, -22...82

To Find :- The number of term for the 82 th term of the Ap.

Solution:-

Let, the first term of the Ap is a

The common difference is d

so,

The fist term is -7

The common difference = ( -12 + 7 ) = -5

Let , the n term of the ap is 82

a + ( n - 1 )d = 82

-7 + ( n - 1 ) -5 = 82

( n - 1 ) -5. = 82 + 7

( n - 1 ) -5 = 89

( n - 1) = $\dfrac{89}{-5}$

n = $\dfrac{-89}{5} + 1$

n = $\dfrac{-84}{5}$

n = -16.8

n = -17

Therefore, the -17th term of an Ap is 82