Question 755601
Brian = x
Katy = x + 4
Chloe = x - 3
x + (x + 4) + (x - 3) = 40
       3x  + 1 = 40
             3x = 40 - 1
             3x = 39
              x = 13
Brian is 13 yrs old
Katy is 17 yrs old.
Chloe is 10 yrs old.
Proof:
 13 + 17 + 10 = 40
           40 = 40
Hope this helps
:-)