The rectangle of blocks below represents what happens when $\frac{1}{3}$13 is multiplied by $\frac{1}{5}$15.
The sides of the rectangle both represent $1$1 and all of the blocks together make up $1$1 whole.
$\frac{1}{5}$15  
$\frac{1}{3}$13 

Using the block representation, evaluate $\frac{1}{3}\times\frac{1}{5}$13×15.