Answer :
[tex]x-\ number\ of\ five\ dollar\ bills\\
y-\ number\ of\ ten\ dollar\ bills\\\\
\left \{ {{x=y+24} \atop {5x+10y=540}} \right. \\\\
substotute\ x=y+24\ to\ the\ second\ equation\\\\
5(y+24)+10y=540\\\\
5y+120+10y=540\\\\
15y+120=540\ \ \ | subtract\ 120\\\\
15y=420\ \ \ | divide\ by\ 15\\\\
y=28\\\\
x=y+24=28+24=52\\\\
There\ are\ 52\ five\ dollar\ bills\ and\ 28\ ten\ dollar\ bills.[/tex]