Question 19378
LET JIMMY BE X YEARS
THEN TODAY ZACK 'S AGE Y= X+2
ONE YEAR BACK AGE OF ZACK (Y-1)= 3(X-1) 
                                = 3X -3
                               Y=3X-3 +1
                                 = 3X -2
BUT Y= X + 2

X+ 2 = 3X -2

  4 = 3X-X
  4 = 2X
  2 = X
 Y = 4
JIMMY IS 2 YRS OLD AND ZACK IS 4 YRS OLD.