Final answer:
The fraction of the boxes with r's in them is 4/10 or 0.4 as a decimal number.
Step-by-step explanation:
The fraction of the boxes with r's in them can be found by counting the number of boxes with r's and dividing it by the total number of boxes. In this case, there are 4 boxes with r's and 10 total boxes, so the fraction is 4/10. To write this as a decimal number, you divide 4 by 10, which equals 0.4.