Divide both sides by 5:
simplified = 3/7
Hope this helps!
So first, you add all the numbers together
8.40*3=25.20
12.89*2=25.78
18.90*1=18.90
____________
$69.88
Divide the number of shirts: 6 by the total amount
69.88
_____ = $11.64666= $11.65 is your answer!
6