Question

Please reply at the earliest !!!
Arithmetic Progressions (AP) Class 10

Answer 1

Given:-

$l = 28$

S = 144

n = 9

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To Find:-

a = ?

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Solution:-

By using formula:-

$S = \frac{n}{2} (a + l)$

$144 = \frac{9}{2} (a + 28)$

$144 \times \frac{2}{9} = a + 28$

$16 \times 2 = a + 28$

$32 = a + 28$

$32 - 28 = a$

$4 = a$

$\boxed {a = 4}$