Using the numbers [15, 45, 60, 9, 3], create an equation that equals 90. You can use basic arithmetic operations (+, -, *, /) and each number can only be used once. Show your work in <think> </think> tags. And return the equation and target answer in <answer> </answer> tags, for example <answer> (60 / 2) + 9 = 34 </answer>.