A, B, and C go to save money. A and B save 300 yuan, B and C save 280 yuan. It is known that C saves 10% less than A. How much money does A save?
甲、乙、丙三人去存钱，甲乙共存300元，乙丙共存280元，已知丙存的比甲少10%，甲存了多少钱？
<gadget id="calculator">300 - 280</gadget>
<output>20</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">20 / (1/10)</gadget>
<output>200</output>

<result>200</result>