Pipe A fills a tank in 12 hours and pipe B fills it in 6 hours. Working together, how many hours do they need?
Answer and explanation
Correct answer: A. 4 h
- Step 1: In one hour they fill 1/12 + 1/6 = 1/4 of the tank.
- Step 2: So the time is the inverse: 4 hours.
Answer
4 h.
Practise more Permutations, Probability and Sequences.
Free questions with an explanation for every one, and full timed Alberta Diploma Exams mock tests.
More Permutations, Probability and Sequences questions
- A fair coin is tossed 4 times. What is the probability of exactly 2 heads?
- A fair coin is tossed 5 times. What is the probability of exactly 1 head?
- The first term of an arithmetic series is 8, the common difference is 4 and there are 8 terms. What is the sum?
- A fair die is rolled 2 times. What is the probability of getting at least one six?
- A colony of 1000 bacteria doubles every 4 hours. How many bacteria are there after 8 hours?
- What is the minimum value of f(x) = x^2 - 4x + 3?