Question

if a,b,c,d are in AP then prove a+b,b+c,c+d are in AP

Answer 1

a,b,c are in AP then 2b=a+c
We have to prove
2(a+c)=(b+c)+(a+b)
so 2a+2c=2b+a+c
so a+c=2b
Which is true
Hence proved