Question: A person has a total of 50 coins consisting of 10 and 25 cent coins. If the total value is $8.50, how many 25 cent coins does he have?
Options:
Correct Answer: 30
Solution:
Let the number of 10 cent coins be x and 25 cent coins be y. Then, x + y = 50 and 0.10x + 0.25y = 8.50. Solving these gives y = 30.