求数学高手帮我看三道数学题！万分感谢！！！

wangningdatouUID：2506149

1)Anne owes Bob 4dollars,Bob owes Carol 3 dollars , Carol owes Anne 5dollar.If Carol settles all the debts by giving money to both Anne and Bob, how much will she give Anne?
2)A vault holds only 8-ounce tablets of gold and 5-ounce tablets of silver.If there are 130 ounces of gold and silver total, what is the greatest amount of gold that can be in the vault, in ounces?
这一道读不明白题：Bill purchases an item and receives no change.Before the purchase, he had only a -five dollar bill,two ten-dollar bills, and a twenty-dollar bill. How many distinct possibilities are there for the total amount of his purchase?
多谢了！！！！

liyd10UID：2656817

1) 1
2) 64
3) 12
Am I right?

edwardzwzUID：2425379

1. Carol give 1 dollar to Anne and give 1 dollar to Bob, then she settles all the debts.
2. 120 ounces. 8x+5y=130, try the maximum x, x=15.
3. 9 possibilities. 5, 10, 15, 20, 25, 30, 35, 40, 45

applechewUID：2493981

3# edwardzwz

我和你做的一样