A batch of goods was transported away (1/5) for the first time, and 30 tons for the second time, ___________. The formula for finding the total tonnage of this batch of goods is: (30+18)/(1-(1/5)), the condition that should be supplemented is how many tons are left
一批货物，第一次运走了(1/5)，第二次运走30吨，___________．求这批货物的总吨数列式是：(30+18)/(1-(1/5))，应补充的条件是还剩多少吨
<result>18</result>