<PRE><B>Question 1031367</B>
In terms of feet:
(A) {{{ y = 3 + (15/12)*x }}}
(B) {{{ y = 4 + (10/12)*x }}}
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(A) {{{ y = ( 5/4)*x + 3 }}}
(B) {{{ y = ( 5/6 )*x + 4 }}}
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Here are the plots of the 
2 lines:
{{{ graph( 400, 400, -10, 20, -10, 20, 3 + (5/4)*x, 4 + (5/6)*x ) }}} 
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To find the intersection, set A = B
{{{  ( 5/4)*x + 3 = ( 5/6 )*x + 4 }}}
Multiply both sides by {{{ 12 }}}
{{{ 15x + 36 = 10x + 48 }}}
{{{ 5x = 12 }}}
{{{ x = 12/5 }}}
and
(A) {{{ y = ( 5/4)*(12/5) + 3 }}}
(A) {{{ y = 3 + 3 }}}
(A) {{{ y = 6 }}}
The trees are the same height, 6 ft
in 12/5 years, or 2 yrs 5 months</PRE>