Ursula went to the store and bought butter, bread, a package of cheese, and tea. The bread was 2 times cheaper than the butter, while the price of the butter was 80% of the price of cheese. Tea was the most expensive and cost twice the price of a package of cheese. If the tea cost $10, how much did Ursula pay for her purchases? Let's think first. Chain of thought:
The price of the tea was twice the price of the cheese, so the cheese cost was 10 / 2 = $5. The price of the butter was 80 / 100 * 5 = $4. If the bread was 2 times cheaper than butter, that means it cost 4 / 2 = $2. That means Ursula paid for all her shopping 2 + 4 + 5 + 10 = $21.
Therefore, the answer is 21.