Question

in an AP the first term is -4 and the last term is 29 and the sum of all its terms is 150 find its common difference​

Answer 1

Sₙ = n/2(a + l)

   where, n = number of terms

               a = first term

                l = last term

Sₙ = n/2 * (25) = 150

     =>n = 6 * 2 = 12

so, l = a + (n - 1) * d

   => 29 = -4 + 11 * d

   => d = 33/11 = 3   Ans...