To cook fondant, sugar and water are heated to 230°F. Then the mixture is cooled at room temperature before it is kneaded. If the cooked fondant
cools to 200°F in 15 minutes in a 68°F kitchen, how long will it take to
cool to 100°F? (Hint: Find the constant k first.)

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.