For loading oil, 70 tanks with a capacity of 60m2 are needed. How many such tanks will be required if their capacity is 21m2?

First, let’s find out how much oil fits into seventy tanks with a capacity of sixty square meters:

70 * 60 = 4200.

Four thousand two hundred (liters) fits in seventy tanks with a capacity of sixty square meters.

Now let’s find out how many tanks are needed for the same volume of oil, if the capacity of the tanks is twenty one square meters:

4200: 21 = 200.

Answer: Two hundred tanks will be required if their capacity is twenty-one square meters.