If "P" denotes "multiplied by", "R" denotes "subtracted from", "S" denotes "added to" and "Q" denotes "divided by", then which of the following equation is true?

• 18 R 60 Q 15 S 2 = 8
• 15 S 16 Q 2 P 4 = 47
• 3 P 5 R 18 Q 3 = 6
• 15 S 28 Q 4 P 2 = 27