Final answer:
To calculate the price of 1 kg of silver on January 1, 2015, after a 9.4% decrease, subtract 9.4% of the original price ($607) from the original price.
Step-by-step explanation:
To calculate the price of 1 kg of silver on January 1, 2015, after it had decreased by 9.4%, we can use the following formula:
Price after decrease = Price before decrease - (Price before decrease * Decrease percentage)
Using the given information, where the price of 1 kg of silver on January 1, 2010, was $607 and the decrease percentage is 9.4%, we can substitute the values into the formula:
Price after decrease = $607 - ($607 * 0.094)= $551.98
Rounding the answer to the nearest dollar, the price of 1 kg of silver on January 1, 2015, is approximately $552.