Question

Five years ago the average age of A and B was 20 years. At present the average age of A, B, C is 30 years. C's current How old are you?​

Answer 1

Step-by-step explanation:

let the present age of A be x

let the present age of B be y

and the present age of C be z

case I

x-5+y-5/2=20

x+y-10=40

x+y=50---------(i)

case ii

x+y+z/3=30

x+y+z=90

x+y=90-z-----------(ii)

from eq.i and ii

90-z=50

-z=50-90

-z=-40

z=40

hence ,the present age of C is 40