Question 763257
A's rate of growth = 5% / yr
B's rate of growth = 4% / yr
Let {{{ n }}} = number of years passed
since Jan 2001
Let {{{ P }}} = population
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Equation for A:
(1) {{{ P = 70000*( 1 + .05 )^n }}}
Equation for B:
(2) {{{ P = 60000*( 1 + .04 )^n }}}
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From 2001 to 2003 is 2 years
The difference in their populations in 2 years is
{{{ 70000*( 1 + .05 )^n - 60000*( 1 + .04 )^n }}}
{{{ 70000* 1.05^2 - 60000*1.04^2 }}}
{{{ 70000*1.1025 - 60000*1.0816 }}}
{{{ 77175 - 64896 = 12279 }}}
 at the end of December 2003, A's population
will be 12,279 greater than B's