Question

If a,x,y,z,b are in A.P., and if x+y+z=15 then a+b=
(A)15
(B)10
(C)30
(D)20​

Answer 1

Step-by-step explanation:

x-a=y-x=z-y=b-z (2)

so, x-a=y-x

2x-y=a (1)

2y-z=x

but, x=15-y-z so,

15-y-z=2y-z

y=5

so, x+z=10

x=10-z

putting this in (1)

2(10-z)-5=a

15-2z=a (3)

from (2) ,

2z-5=b

adding the (3) and this equation,

a+b=10