Take 10 kg of 20% salt water and add several kilograms of 5% salt water to obtain 10% salt water. How many kilograms of 5% saline is added?
有浓度为20%的食盐水10千克，加入5%的食盐水若干千克，得到了浓度为10%的食盐水．加入5%的食盐水多少千克．
<result>20</result>