Question 63234
1. {{{ .05n + .10d = 5.65 }}}
2. {{{ .05(n+8) + .10(2d) = 10.45 }}}
solve equation 1 for nickles
{{{ .05n + .10d = 5.65 }}}
{{{ .05n = 5.65 - .10d }}}
divide all parts by .05 
{{{ n = 113 - 2d }}}
substitute this back into equation 2
{{{ .05(n+8) + .10(2d) = 10.45 }}}
{{{ .05(113-2d+8) + .10(2d) = 10.45 }}}
combine like terms
{{{ .05(105-2d) + .10(2d) = 10.45 }}}
distribute
{{{ 5.25 - .1d + .2d = 10.45 }}}
add like terms
{{{ 5.25 + .1d = 10.45 }}}
subtract 5.25 from both sides
{{{ .1d = 5.20 }}}
divide by .1
{{{ d = 52 }}}
He has 52 dimes