Lea's utility function is

U = ln( x ) + 0.8 y

where x denotes her consumption of good X and y denotes her consumption of good Y.

Suppose the government imposes a per-unit tax on good X equal to 9 dollars. The price of good X charged by the sellers of good X is Px = 11 (and does not change due to the tax), the price of good Y is Py = 5 and Lea's income is M = 329.

How much money must we give Lea to compensate her for the price increase due to the tax?