Fifteen persons working 12 hours a day earn Rs. 18,000 per week. How many rupees will 18 persons working 9 hours a day earn per week?

Given:

15 persons working 12 hours a day earn Rs. 18,000 per week.

Formula Used:

Total earnings = Number of persons × Number of hours per day × Number of days per week × Earnings per hour

Calculation:

First, calculate the total number of hours worked by 15 persons in a week:

Total hours worked by 15 persons in a week = 15 × 12 × 7

Total hours = 1260 hours

Next, calculate the earnings per hour:

Earnings per hour = Total earnings / Total hours worked

Earnings per hour = 18000 / 1260

Earnings per hour = 14.29 Rs/hour

Now, calculate the total number of hours worked by 18 persons working 9 hours a day in a week:

Total hours worked by 18 persons in a week = 18 × 9 × 7

Total hours = 1134 hours

Finally, calculate the total earnings for 18 persons working 9 hours a day in a week:

Total earnings = Total hours worked × Earnings per hour

Total earnings = 1134 × 14.29

Total earnings = 16198.86

Rounded to the nearest whole number, the total earnings are Rs. 16,200

The correct answer is option 1.