A $10 bill (1,000 cents) was replaced with 50 coins having the same total value. The only coins used were 5-cent coins, 10-cent coins, 25-cent coins, and 50-cent coins. How many 5-cent coins were used?
1.Exactly 10 of the coins were 25-cent coins and exactly 10 of the coins were 50-cent coins.
2.The number of 10-cent coins was twice the number of 5-cent coins.