Solve the Problem $\frac { 1 } { 2 }$ Inch Thick and the Shelves Are Evenly Spaced

Multiple Choice

Solve the problem.
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Four boards are used as shelves in a bookcase. Each one is $\frac { 1 } { 2 }$ inch thick and the shelves are evenly spaced. If the height, $h$ , of the bookcase is 40 inches, how much space is between each shelf?

A) $9 \frac { 1 } { 2 }$ inches
B) $13 \frac { 1 } { 3 }$ inches
C) $12 \frac { 2 } { 3 }$ inches
D) 10 inches