This is a problem where you should make an equation.
Let's say x is the first week. It would mean
First Week : x
Second Week : x + 5
Third Week : 2(x+5)
You need to add these up to make your equation. Your equation will look something like this :
Now you simplify.
That means they sold 104 Boxes in the First Week.
So they sold 109 Boxes the Second Week.
109 x 2 = 218
And they sold 218 Boxes the Third Week.
I hope I was useful!
Let's say x is the first week. It would mean
First Week : x
Second Week : x + 5
Third Week : 2(x+5)
You need to add these up to make your equation. Your equation will look something like this :
Now you simplify.
That means they sold 104 Boxes in the First Week.
So they sold 109 Boxes the Second Week.
109 x 2 = 218
And they sold 218 Boxes the Third Week.
I hope I was useful!