Question

the common difference of an A.P in which A15-a6 =-27/3 is

Answer 1

we know that nth term of AP is a + (n - 1)d  (where a is the 1st term of AP and d is common difference)

let us find the 15th term

⇒ 15th term of an AP = a + 14d

let us find the 6th term

⇒ 6th term of an AP = a + 5d

Given the difference of 15th term and 6th term is -27/3 = -9

⇒ a + 14d - a - 5d = -9

⇒ 9d = -9

⇒ d = -1

so the common difference of given AP is -1