For this case, we propose a system of two equations with two unknowns.
Let:
x: The variable that represents the number of biscuit boxes sold by Tori Chang
y: The variable that represents the number of biscuit boxes sold by Kai Chang
Between the two they sold 110 boxes of cookies:
[tex]x + y = 110[/tex]
If Kai sold 4 times more boxes of cookies than Tori we have:
[tex]y = 4x[/tex]
We substitute the second equation in the first:
[tex]x + 4x = 110\\5x = 110\\x = \frac {110} {5}\\x = 22[/tex]
Then, Tori Chang sold 22 boxes of cookies.
[tex]y = 4x\\y = 4 * 22\\y = 88[/tex]
Kai Chang sold 88 boxes of cookies.
Answer:
Tori Chang: 22 Boxes
Kai Chang: 88 boxes
