Explanation

600 units are made in 9 days with 20 machines.

To find the number of units made per day, divide 600 by 9: 600 ÷ 9 = 66.67 units per day.

Since there are 20 machines, the number of units made per day per machine is: 66.67 ÷ 20 = 3.33 units per day per machine.

Now, if we have 18 machines and want to produce units for 12 days, the total units that can be made are: 3.33 units per day per machine × 18 machines × 12 days = 720 units.

So, with 18 machines, the soap factory can produce 720 units in 12 days.