Question

Check whether – 150 is a term of the AP :11,8,5,2…. ?

Answer 1

First term of AP is a= 11
Common difference is d = -3
So Tn = a+(n-1)d
-150 = 11+(n-1)(-3)
-161 = (n-1)(-3)
$\Rightarrow n-1=\frac{161}{3}$ which is not a natural number so -150 is not a term of the given AP.