Question 860107
{{{ 1/4 - .05*( 1/4 ) = ( 1 + x ) / ( 4 + .2 ) }}}
{{{ .95*( 1/4) = ( 1 + x ) / 4.2 }}}
{{{ .95 = ( 1 + x )*( 2/2.1 ) }}}
{{{ 1.995 = 2 + 2x }}}
{{{ 2x = -.005 }}}
{{{ x = -.0025 }}}
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The new ratio is:
{{{ ( 1 + x ) / 4.2 = .9975 / 4.2 }}}
The % decrease in the price of the keyboard is:
{{{ .0025}}} = .25%
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check:
{{{ .95*( 1/4) = ( 1 + x ) / 4.2 }}}
{{{ .95*( 1/4) = ( 1 - .0025 ) / 4.2 }}}
{{{ .95*.25 = .9975 / 4.2 }}}
{{{ .9975 = .95*.25*4.2 }}}
{{{ .9975 = .9975 }}}
OK