12 girls can do a a piece of work in 30 days, working 8 hours a day . In how many days 18 girls can do the same piece of work while working 4 hours a day?

To solve this problem, we first need to find out the total hours required to complete the work by 12 girls.

Step 1: Total hours required by 12 girls to complete the work = Number of girls * Number of days * Hours per day = 12 girls * 30 days * 8 hours/day = 2880 hours

This means that the work requires 2880 hours to be completed by one girl.

Step 2: Find out how many hours 18 girls can work in a day = Number of girls * Hours per day = 18 girls * 4 hours/day = 72 hours

This means that 18 girls can work a total of 72 hours in a day.

Step 3: Find out the number of days required for 18 girls to complete the work = Total hours required to complete the work / Hours that can be worked by 18 girls in a day = 2880 hours / 72 hours/day = 40 days

So, 18 girls can complete the work in 40 days if they work 4 hours a day.