A trader bought a product for $$ $200$$. If he sells his product $$50 \%$$ above cost and gives a Christmas discount of $$10 \%$$, find his profit during Christmas.  John attempted to answer the question in this way:  He sold the product at $45 \%$ above cost since $50 \% \times 0.1 = 45 \%$, hence he sold the product at $200 \times 1.45 =  $290$.  Therefore his profit is $290-200 =  $90$.  Is he right or wrong? If not, solve for the correct answer. 
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