Question

If 4,x,20 are in a.p then find x

Answer 1

Answer:

Correct option is

A

11

Given 20,x+1,4 are in A.P.

a=20

n=3

1) d=a

2

−a

1

∴d=x+1−20

∴d=x−19 (1)

2) d=a

3

−a

2

∴d=4−(x+1)

∴d=4−x−1

∴d=3−x (2)

From (1) and (2),

x−19=3−x

∴2x=22

∴x=11