There are two kinds of salt water, A and B. The concentration of A is 20%, and the concentration of B is 10%. Now it is necessary to prepare 100 grams of salt water with a concentration of 15%. How many grams of each of the two kinds of salt water are needed?
有甲乙两种盐水，甲的浓度为20%，乙的浓度为10%，现要配制100克浓度为15%的盐水，问需甲乙两种盐水各多少克？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">100 * (3/20)</gadget>
<output>15</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

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

<gadget id="calculator">5 / (1/10)</gadget>
<output>50</output>

<result>50</result>