Answer: As i understand, we have two types of sheets, ones with 4 yards long, and others with 5 yards long.
if Roland needs 8 sheets of 4 yards, how many sheets of 5 yards will he need?
you can see this as:
8*4 = x*5
so x = 8*4/5 = 6.4
so Roland will need 6.4 sheets of 5 yards.