A liquid medicine is prepared by adding 3 milliliters of liquid medicine to 100 milliliters of normal saline. How many liters of such a liquid medicine can be prepared with 15 liters of liquid medicine now? (Solve with ratio)
一种药水是用100毫升生理盐水加入3毫升药液配制而成．现在有15升药液可配制这样的药水多少升？(用比例解)
<result>15</result>