You can multiply 0.15 and 100, and you will get 15.
-OR-
You can move the decimal points two places to the right since 100 has two zeros. (You could move it to the right three if it were 1000 because it has three 0s)
Answer = $55 Because 3 + 7 + 5 = 15 The 3 = black coffee The 7 = sugar coffee And the 5 = milk coffee So then u do 5/15 simplified = 1/3 So then do 1 /3 of $165 = $55