Question 1132795
I'll take a shot at this
The weekly payments would include
compounded interest on the principle
{{{ A = P*( 1 + r/n )^(n*t) }}}
{{{ A = 17.85*52*2.5 }}}
{{{ A = 2320.5 }}}
{{{ n*t = 52*2.5 }}}
{{{ n*t = 130 }}}
{{{ r/n = .13/52 }}}
{{{ r/n = .0025 }}}
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{{{ 2320.5 = P*( 1 + .0025 )^130 }}}
{{{ 2320.5 = P*1.0025^130 }}}
{{{ 2320.5 = P*1.38347 }}}
{{{ P = 1677.3 }}}
The selling price was $1,677.30 
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check:
{{{ I = 2320.5 - 1677.3 }}}
{{{ I = 643.2 }}}
{{{ 17.85*52 - 643.2 = 1677.3 }}}
OK