Which term of the A.P. 53, 48, 43, .... is the first negative term?

Let us first evaluate which term is 0 because the next term will be the term containing first negative number. a = 53, d = 48 - 53 = -5, a n = 0. By formula, a n = a + (n - 1)d ⇒ a n = 53 + (n - 1)(-5) ⇒ 0 = 53 - 5n + 5 ⇒ 5n = 58 ⇒ n = The next term will be containing the first negative number. Hence, the 12th term will contain the first negative number.