Question 1052962
The formula is 
{{{V = L*W*H }}}
{{{ V }}} = volume
{{{ L }}} = the length
{{{ W }}} = the width
{{{ H }}} = the height
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You are given:
{{{ V = 160 }}} in3
{{{ W = L - 3*12 }}} in
{{{ H = 4 }}} in
( note I converted {{{ 3 }}} ft to inches )
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Plug data into formula and 
find {{{ L }}} and {{{ W }}}
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This is possible because you have
2 equations and 2 unknowns