Question

Given l = 28, S = 144 and there are 9 terms. Find a​

Answer 1

Answer:

4

Step-by-step explanation:

Given :

• l = a9 = a + 8d = 28
• S9 = 144

Sn = ⁿ/2 [a + l]

⇒ 144 = 9/2 [a + 28]

⇒ 144 × 2/9 = a + 28

⇒ a + 28 = 32

⇒ a = 32 - 28

⇒ a = 4