There will be 50 gift bags.
The first set of 25 bags
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Because there are 25 thumb drives, the first 25 bags will each have 1 thumb drive.
Also, each bag will have 5 times as many key chains as a thumb drive. Therefore each of the first 25 bags will have
1 thumb drive, 5 key chains.
After the first 25 bags, we have used
25 thumb drives, 5*25 = 125 key chains.
The second set of 25 bags
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We have a total of 200 key chains, so we have 200-125 = 75 key chains left.
Distribute them equally among the remaining 25 bags, so each bag has
75/25 = 3 key chains.
Answer:
25 bags, each with 1 thumb drive and 5 key chains.
Another 25 bags, each with 3 key chains.