Answer the following question, with explanation first.
Tilly needs to sell 100 bags at $10 per bag to make $300 in profit. How much did she buy each bag for?

7
Tilly will make 100 x $10 = $1000 in total.

She has spent $1000 - $300 = $700 on 100 bags.

Each bag cost Tilly $700 / 100 = $7.

.

So, the final answer is 7