解：設(shè)????$1$????角、????$5$????角、????$1$????元的硬幣各取了????$x$????枚、????$y$????枚、????$z$????枚
根據(jù)題意，得
????$ {{\begin{cases} { {x+y+z=15，①}} \\{0.1x+0.5y+z=7，②}\end{cases}}}$????
????$ ②×10-①，$????得
????$ z=\frac {55-4y}9$????
因?yàn)????$y，$????????$z$????都為整數(shù)，則????$y=7，$????????$z=3$????
把????$y=7，$????????$z=3$????代入①，得????$x=5$????
所以方程組的解為????${{\begin{cases} { {x=5}} \\{y=7} \\{z=3} \end{cases}}}$????
答：????$1$????角、????$5$????角、????$1$????元的硬幣各取了????$5$????枚、????$7$????枚、????$3$????枚
