Answer:
After 15 days they'll both have $10
Explanation:
100 (Xavier's total)- 6x (6 dollars every day) = 160 (Zach's total amount) -10x (10 dollars every day)
[tex]100-6x=160-10x\\[/tex]
+10x on both sides
[tex]100+4x=160[/tex]
-100 on both sides
[tex]4x=60[/tex]
/4 on both sides
[tex]x=15[/tex]