U just have to find original amount (100%) and that is the amount he made last week.
Answer:

Step-by-step explanation:
<u>Step 1: Determine the area of the black area</u>



<u>Step 2: Determine the area of the entire white and black area</u>



<u>Step 3: Determine the difference to just get the white area</u>


Answer: 
There are no irrational numbers because all these fractions come to a stop