Question 995562
In 1 day, the 600 men consume {{{ 1/25 }}} 
of the provisions
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In 1 day, each of the 600 men consume 
{{{ ( 1/600 )*( 1/25 ) = 1/15000 }}} of the 
provisions
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After 9 days, the 600 men consume {{{ 9/25 }}}
of the provisions
That means there is {{{ 1 - 9/25 = 16/25 }}}
of the provisions left
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{{{ 16/25 }}} was consumed in 4 days
[ rate for 1 man in 1 day ] x [ 600 + n men] x [ 4 days ] = [ fraction of provisions left ]
{{{ ( 1/15000 )*4*( 600 + n ) = 16/25 }}}
{{{ 4*( 600 + n ) = ( 16/25 )*15000 }}}
{{{ 600 + n = ( 4/25 )*15000 }}}
{{{ n = 2400 - 600 }}}
{{{ n = 1800 }}}
1800 men were added
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check:
{{{ 1800 + 600 = 2400 }}}
{{{ ( 1/15000 )*4*2400 = .64 }}}
{{{ 16/25 = .64 }}}
OK
Definitely get a 2nd opinion on this.
It is a little tricky for me