Answer :
Per concert: $25
Per T-shirt: 50¢ = $0.50
If she sold 174 T-shirts at one concert, then:
[tex]\$25+174\cdot\$0.50=\$25+\$87=\$112[/tex]Finally, knowing that Kat must pay 10% in taxes, her net income is:
[tex]\frac{90}{100}\cdot\$112=\$100.80[/tex]