$2-3.$ The floor system used in a school classroom consists of a $4-$in$.$ reinforced stone concrete slab. Sketch the loading that acts along the joist $BF$ and side girder ABCDE. Set $a=10ft,b=30ft.$ Hint: See Tables $1\mathrm{.}2$ and $1\mathrm{.}4.$

$2-4.$ Solve Prob. $2-3$ with $a=10ft,b=15ft.$

$2-5.$ Solve Prob. $2-3$ with $a=7\mathrm{.}5ft,b=20ft.$