Assuming the sheet is a square
see diagram
the length will be 20-2x
the width will be 20-2x
and the height will be x
the volume will be (20-2x)(20-2x)(x)
First one and the last one are rational. And the other two of them are irrational.
Answer: A
If he has 15$ then he could spend all of it on the colored pencils, so there has to be a black dot on 15, & if he could buy the colored pencils less than 15$ then it has to be a black dot on 15 & an arrow pointing to less than 15
I hope this answers your question
2 3/5 or 2 6/10 is the answer