The task is to generate the correct answer for a given math problem.

[Q]: Problem: if | x - 9 | = 3 x , then x = ?
[A]: - 4.

[Q]: Problem: a customer went to a shop and paid a total of $ 40 , out of which $ 1.28 was for sales tax on taxable purchases . if the tax rate was 8 % , then what was the cost of the tax free items ?
[A]: $ 22.72

[Q]: Problem: a sells a bicycle to b and makes a profit of 25 % . b sells the same bicycle to c at a profit of 50 % . if the final s . p . of the bicycle was rs . 225 , find out the cost price of the bicycle for a .
[A]:
12