John decided to buy 10 pins for himself. They are normally $20 each but they were on sale for 15% off. How much did he spend on pins? Let's be accurate as possible.
The sell reduced the price of each pin by 20 * .15 = $3. So he paid 20 - 3 = $17 per pin. So the total cost was 17 * 10 = $170.
The answer: 170.