Civil Service Exam Reviewer · Word Problems · hard
A pipe can fill a tank in 9 hours, while a drain can empty it in 12 hours. If both are open, how long will it take to fill the empty tank?
- 5.14 hours
- 3 hours
- 10.5 hours
- 36 hours
Answer
D. 36 hours
Solution
Net rate = 1/9 − 1/12 = 1/36 tank/hour → 36 hours.
More Word Problems questions
- Three consecutive odd integers are such that the sum of the first and the third is 82. What is the largest of the three?
- A delivery van traveled 210 km in 5 hours. Part of the trip was at 50 km/h and the rest at 40 km/h. How many hours did it travel at 50 km/h?
- If students sit 4 to a bench, 12 students have no seat. If they sit 5 to a bench, 3 bench(es) are left empty. How many students are there?
- Marco can finish a job in 10 days, Sofia in 12 days, and a third worker in 15 days. How long will the job take if all three work together?
- What is the smaller angle between the hour and minute hands of a clock at 12:45?
- A train 120 m long travels at 108 km/h. How long does it take to completely cross a bridge 360 m long?
- ₱240,000 was invested, part at 6% and the rest at 10% simple annual interest. The total interest after one year was ₱15,600. How much was…
- The sum of the digits of a two-digit number is 10. If the digits are reversed, the new number is 36 less than the original. What is the…
- The sum of the ages of Liza and Ana is 53. 9 years ago, Liza was 4 times as old as Ana. How old is Ana now?
- Tess leaves a town driving at 50 km/h. 1 hour(s) later, Ben leaves the same town on the same road at 70 km/h. How long after Ben starts…