The correct answer is one doughnut cost 2$
A² + b² = c²
20² + n² = (n+2)²
400+ n² = (n+2)(n+2)
400 + n²=n² + 2n + 2n +4
400 + n² = n² +4n +4
400 + n²-n² = n²-n² + 4n+4
400 = 4n + 4
400-4 = 4n +4-4
396 = 4n
396/4 = 4n/4
n= 99
20²+ 99² = (99+2)²
400 + 9801 =10201
10201=10201
$45>(or equal to)$12.99n you can spend less then or equal to forty five dollars without going into debt.