John consumes two goods, X and Y, given the following utility function: U = X 3 Y 2 The price of X (Px) = $10 , and the price of Y (Py) = $20. I...

John consumes two goods, X and Y, given the following utility function:

U = X3Y2

 The price of X (Px) = $10 , and the price of Y (Py) = $20.

I already solved for the answer x=54 and y=18. The next part of the question is: Say John's friends would want him to buy an equal amount of X and Y.  How much money they would need to pay him, on top of his current income, in order for John to agree to do this voluntarily?