Question

if in ap d= 0and the sum of 20 terms is 80 then find its 15 term​

Answer 1

Answer: 15th term =a=4

Step-by-step explanation:

d=0 and S20=80

So a=4

*see detailed answer below in fig

Answer 2

Answer:

d = 0

n = 20

sn = 80

an = a + (n - 1) d

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

80 = a/2 (2a + (20 - 1)0)

80 = a/2 (2a + 0)

80 x 2 = a( 2a + 0)

160 = 2a2

a2= 160/2

a2= 80

a = 4 x root of 5

an= 4 x root of 5 + (15 - 1)0

an= 4 x root of 5