Tilly needs to make a profit of $300 by selling 100 bags at $10 per bag.
The total revenue from selling 100 bags would be 100 x $10 = $1000.
To make a profit of $300, the total cost of purchasing the bags must be $1000 - $300 = $700.
Since Tilly bought 100 bags, the cost of each bag would be $700 / 100 = $7.
Therefore, the cost of each bag that Tilly bought was $7.
#### 7
The answer is: 7
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
If Tilly needs to make a profit of $300 by selling 100 bags at $10 per bag, what was the cost of each bag that she bought?

### Answer:
