Question

if 4,a,b,28 are in arithmetic progression then the value of 'b' is​

Answer 1

Answer:20

d = 8

a= 4

a + 3d = 28

Using elimination

3d = 24 = 24/3 = 8

In short subtract 8 (common difference) from fourth term and b = 20

:-)

Answer 2

Given ; 4,a,b,28 are in arithmetic progression

To Find; value of b

Solution; a1=4 , a2=a ,a3=b,a4= 28, d is unknown

an=a+(n-1)d

a4=a1+3d

28=4 +3d

8=d

a3=a+2d=4+8*2=20

Hence the value of b is 20