<PRE><B>Question 992007</B>
 a plane is climbing to its cruising altitude and is currently 1/4 of the way up.
 after climbing another 16000 feet, it is 2/3 of the way.
 what is the final cruising altitude of the plane?
:
let a = the cruising altitude
{{{1/4}}}a + 16000 = {{{2/3}}}a
16000 = {{{2/3}}}a - {{{1/4}}}a
common denominator
16000 = {{{8/12}}}a - {{{3/12}}}a
16000 = {{{5/12}}}a
multiply both sides by {{{12/5}}}
{{{12/5}}}*16000 = a
cancel the 5
12 * 3200 = a
a = 38,400 ft cruising altitude
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