still stuck on this one please help

Question

Marissa plans to use 50 sheet of aper for a scrapbook. How much thicker will the scrapbook be if she uses heavyweight (which is 2/5 in for 100 sheets) instead of lightweight paper (which is 3/10 in for 100 sheets)?

Answer 1

Using the "heavy weight", she will have a thickness of 1/5 inches
Using the lighter paper she will have a thickness of 3/20 inches

so 1/5 - 3/20
= 4/20 - 3/20 = 1/20

Answer 2

Thank you!