



 
Hi April, If Count Taxula gives p% of his income to charity he gives p/100 × $27,000 which leaves him with
He has to pay a tax of (35  1.8p)% on this remaining amount, so his tax is
Thus after charitable giving and taxes he is left with
This is the expression you need to maximize for 0% ≤ p ≤ 19.44% I hope this helps,  


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