Two cups of salt water in A and B each have 40 grams, and the concentration ratio is 3:2. Add 60 grams of water to B, then pour how many grams into A, and then add water to A and B to make them both 100 grams , then the concentration ratio is 7:3.
A、B两杯食盐水各有40克，浓度比是3：2，在B中加入60克水，然后倒入A中多少克，再在A、B中加入水，使它们均为100克，这时浓度比为7：3．
<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<result>25</result>