Answer:
The answer to your question is 16.27
Explanation: 
You would start with the equation, 
15.35 + 6% = C (Cost) 
15.35 · 6% = 0.921
15.35 + 0.921 = 16.271
Round the one down, since it is less than four, and you get 16.27
Hope this helps. 
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