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- Question
Two taps X and Y can fill a tank in 15 hours and 20 hours respectively. If the two taps are opened at 2 p.m., then at what time (in p.m.) should the tap X be closed to completely fill the tank at exactly 2 a.m.?
Options- A. 8
- B. 7
- C. 9
- D. 10
- Correct Answer
- 8
- 1. A swimming pool is filled in 10 hours by three tankers A, B and C. The tanker C is twice as fast as B and B is twice as fast as A. How much time will tanker A alone take to fill the swimming pool?
Options- A. 90 hours
- B. 40 hours
- C. 70 hours
- D. 80 hours Discuss
- 2. Two pipes, when working one at a time, can fill a cistern in 3 hhrs and 4 hrs, resp while a third pipe can drain the cistern empty in 8 hrs. All the three pipes were opened together when the cistern was 1/12 full. How long did it take for the cistern to be completely full?
Options- A. 2 hrs
- B. 1 hr 45 min
- C. 2 hr 10 min
- D. 2 hr 11 min Discuss
- 3. An electric pump can fill a tank in 2 hours. Because of a leak in the tank, it was taking 21?2 hours to fill the tank. The leak can drain all the water off the tank in how many hours?
Options- A. 9
- B. 10
- C. 10.5
- D. 11.5 Discuss
- 4. A cistern has one inlet, L and one inlet, M. L takes 5 hours to fill the empty tank, when M is not open and M takes 8 hours to empty the full tank, if the tank is two fifth full, how much time will it take to fill the tank completely when both L and M are opened simultaneously? (in hours)
Options- A. 5 hours
- B. 3 hours
- C. 6 hours
- D. 8 hours Discuss
- 5. A water tank is 2/5 th full. Inlet A can fill the tank in 12 minutes while an outlet pipe B can empty it in 6minutes. If both the pipes are open, how long will it take to empty or fill the tank completely?
Options- A. It fills in 4.8 min
- B. It empties in 4.8 min
- C. It fills in 5.6 min
- D. It empties in 5.6 min Discuss
- 6. A bag contains 6 white and 4 black balls .2 balls are drawn at random. Find the probability that they are of same colour.
Options- A. 1/2
- B. 7/15
- C. 8/15
- D. 1/9 Discuss
- 7. A problem is given to three students whose chances of solving it are 1/2, 1/3 and 1/4 respectively. What is the probability that the problem will be solved?
Options- A. 1/4
- B. 1/2
- C. 3/4
- D. 7/12 Discuss
- 8. Two cards are drawn at random from a pack of 52 cards.what is the probability that either both are black or both are queen?
Options- A. 52/221
- B. 55/190
- C. 55/221
- D. 19/221 Discuss
- 9. A man and his wife appear in an interview for two vacancies in the same post. The probability of husband's selection is (1/7) and the probability of wife's selection is (1/5). What is the probability that only one of them is selected ?
Options- A. 2/7
- B. 1/7
- C. 3/4
- D. 4/5 Discuss
- 10. In a lottery, there are 10 prizes and 25 blanks. A lottery is drawn at random. What is the probability of getting a prize?
Options- A. 2/7
- B. 5/7
- C. 1/5
- D. 1/2 Discuss
Pipes and Cistern problems
Search Results
Correct Answer: 70 hours
Correct Answer: 2 hrs
Correct Answer: 10
Correct Answer: 8 hours
Explanation:
Then 3/5 th tank fill in =40/3 * 3/5= 8 hours
Correct Answer: It empties in 4.8 min
Correct Answer: 7/15
Explanation:
Let S be the sample space
Then n(S) = no of ways of drawing 2 balls out of (6+4) = 10 = =45
Let E = event of getting both balls of same colour
Then,n(E) = no of ways (2 balls out of six) or (2 balls out of 4)
= = = 15+6 = 21
Therefore, P(E) = n(E)/n(S) = 21/45 = 7/15
Correct Answer: 3/4
Explanation:
Let A, B, C be the respective events of solving the problem and be the respective events of not solving the problem. Then A, B, C are independent event
are independent events
Now, P(A) = 1/2 , P(B) = 1/3 and P(C)=1/4
P( none solves the problem) = P(not A) and (not B) and (not C)
=
=
=
=
Hence, P(the problem will be solved) = 1 - P(none solves the problem)
= = 3/4
Correct Answer: 55/221
Explanation:
We have n(s) = 52 = 52*51/2*1= 1326.
Let A = event of getting both black cards
B = event of getting both queens
A?B = event of getting queen of black cards
n(A) = = = 325, n(B)= = 4*3/2*1= 6 and n(A?B) = = 1
P(A) = n(A)/n(S) = 325/1326;
P(B) = n(B)/n(S) = 6/1326 and
P(A?B) = n(A?B)/n(S) = 1/1326
P(A?B) = P(A) + P(B) - P(A?B) = (325+6-1) / 1326 = 330/1326 = 55/221
Correct Answer: 2/7
Correct Answer: 2/7
Explanation:
Total number of outcomes possible, n(S) = 10 + 25 = 35
Total number of prizes, n(E) = 10
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