A bag contains a total of 200 dimes and nickels. Without looking, a student chooses a coin, records the type and places it back in the bag. The student records 12 dimes and 13 nickels. What is the best prediction of the the total number of dimes in the bag?

96

Explanation:

The proportions of dimes and nickels in the withdrawls recorded by the student are:

dimes: 12/25 nickels: 13/25

Thus, the best prediction of the total number of dimes in the bag is found using the same ratio of dimes:

dimes in the bag = (12/25) * 200 = 96 ← answer