Some problems about rates, work, percent
[#permalink]
04 Nov 2016, 16:21
I send you some problems. I really appreciated to solve
1. A juice company owns 2 machines for its production, P and Q, which produce 30 litres and 60 litres per minute respectively at a constant rate. The daily production is 21,600 l. For daily production, machine P operates alone for half the time and then both machines are used for the other half. What is the total daily operating time (in minutes) for machine P?
2. Catalina wants to record a 1 hour documentary which starts at 10:30 p.m. At 7:00 a.m., she programs the timer to initiate the recording at 10:30 p.m. of the same day and stop the recording 60 minutes later. Catalina’s recorder is 30 seconds late every hour. Her documentary begins on time. What amount of time (in seconds) of the program will she lose?
3. Jaime gained 25% of his original weight in a year. During the following year he intends to regain his original weight and loses half a kilo per month during the entire year. At the end of the year, he still has 3 kilos left to lose. What was his original weight?
4. An office has a ratio of 3 women to 7 men. If the office has a total of 110 employees and intends to hire 15 men, how many women should the office hire to get a proportion of 50% men- 50% women?
5. At the end of the season’s first half, the soccer team won just one third of the 51 points available (3 points per game). Calculations show that 50% of all season points are required to participate in the playoffs. If the team wins 33 points in the season’s second half, how many points would they still need to participate in the playoffs?
6. A painter needs 5/4 liters of paint A and 3/2 of paint B in order to paint 1 m2; if he has a total of 110 liters of paint in adequate proportions of paints A and B, how many m2 can he paint?
7. In a hairdresser it takes Carolina 24 minutes to complete a cut, while Pamela takes just 21 minutes. If they both start working at 9am, what is the next time at which they will start cutting a customer's hair at the same moment?
8. Elisa has a total of 4 exams for her semester. She had a score of 78 at her first exam. What should be the average of her next 3 exams to obtain a total average score of 87?
9. Of those surveyed in a poll, 60% were Chilean. If 75% of the Chileans polled were males and 55% of the non-Chileans polled were males, what percent of those polled were males?
10. It takes 5 hours for machine A to empty half a pool. Machine B takes 7.5 hours to do the exact same job. How many hours would it take for the two machines working together to empty the whole pool?