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## Answers

S3 =n/2[2a+(n-1)d]=36

3/2[2a+(3-1)d] =36

2a+2d =36 x 2/3

2a +2d =24.......let the equation be 1

a5 =15

(a +4d =15) x 2

2a + 8d = 30.....let the equation be 2

equation 2-1, gives

2a +8d =30

2a + 2d =24

⇒6d = 6

⇒d =1

substitute in any equation

2a + 2d =24

2a +2x1 =24 (d=1)

2a +2 =24

2a =24-2

2a=22

a=22/2

⇒a=11

⇒a1 = a =11

a2 =a+d =11+1 =12

a3 = a=2d = 11+2x1 =11+2 =13

a4 =a+3d = 11+3x1 =11+3 =14

__∴The series is 11,12,13,14,15............__