Question

(ii) The sum of the first 45 terms of an A.P. is 3150. Find its 23rd term.​

Answer 1

Answer:

70

Step-by-step explanation:

Sn = n/2(2a + (n-1)d)

S45 = 3150

23rd term = a + 22d

$3150 = \frac{45}{2} (2a + (45 - 1)d) \\ 3150 = \frac{45}{2} (2a + 44d) \\ 3150 = \frac{45}{2} \times 2 \times (a + 22d) \\ 3150 = 45(a + 22d) \\ \frac{3150}{45} = a + 22d \\ 70 = a + 22d$

therefore the 23rd term = 70

Hope you get your answer