Nate and Ellie sold 90 boxes of cookies. If Nate sold one third of this, find the proportion of the cookie boxes that Nate sold to the quantity of boxes ellie sold.

Ellie sold 2/3 of the total quantity of boxes

Step-by-step explanation:

Since Nate sold 1/3 of the 90 boxes, that is 1/3*90 = 30 boxes, then the remaining boxes were sold by Ellie, thus

Boxes sold by Ellie = 90 boxes in total - 30 boxes sold by Nate = 60 boxes

thus Ellie sold a proportion of 60 boxes/90 boxes in total = 2/3

therefore Ellie sold 2/3 of the total

we can verify this since since the sum of the proportion sold by Ellie and Nate should be the total

2/3 by Ellie (66.67%) + 1/3 by Nate (33.33%) = 1 (100%, the total)