Using the numbers [6, 25, 23, 10], create an equation that equals 15. You can use basic arithmetic operations (+, -, *, /) and each number can only be used once. Show your work in <think> </think> tags. And return the final equation and answer in <answer> </answer> tags, for example <answer> (6 + 23) / (25 / 10) = 15 </answer>. 