A book shelf is 3 1/2 feet long. Each book on the shelf is 5/8 inches wide. How many books will fit on the shelf?

First convert 3 and 1/2 to imporoper

3 and 1/2=6/2+1/2=7/2 feet

convert to inches

7/2 times 12=84/2=42 inches

k so

total space used=number of books times space each book uses

total space possible=42

space each book uses=5/8

so

42=numberofbooks times 5/8

multiply both sides by 8/5 to clera fraction (5/8 times 8/5=40/40=1)

336/5=number of books

67.2=number of books

since you cannot fit 0.2 book (besides being useless or very small), we round down

67 books