THE CORRECT ANSWER IS:
Mary sells 43 units; Jay sells 51 units; Abby sells 54 units
HOPE THIS HELPFUL. :)
Michael's present age is 53
Step-by-step
17-4=13
John is 13
than when John will be 49
u add 4 to 49
4+49=53
so Michael is 53 because he is 4 years older :)
The mathematical answer would happen to be... 0