Answer
262 ft
Work Step by Step
Multiply to find the total length of pipe on hand for each size, then sum to find the total length of pipe on hand.
$3\times12=\overset136$
$8\times8=\ \ 64$
$9\times10=90$
$12\times6=\underline{72}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 262$
