Central Exam — Quantitative Aptitude
UPSC · SSC · Bank · Railway · NDA — Central Government Exam MCQ Practice
Showing 911–920 of 1,106 questions
Q.911
Easy
Time and Work
A pipe can fill a tank in 20 hours and another pipe can empty it in 30 hours. If both pipes are opened together, in how many hours will the tank be filled?
Correct Answer:
B. 60 hours
Explanation:
Fill rate = 1/20, Empty rate = 1/30. Net rate = 1/20 - 1/30 = 1/60. Time = 60 hours
Q.912
Easy
Time and Work
If 24 workers can build a wall in 16 days, how many workers are needed to build the same wall in 12 days?
Correct Answer:
C. 32 workers
Explanation:
Total work = 24 × 16 = 384 worker-days. For 12 days: 384/12 = 32 workers
Q.913
Easy
Time and Work
A costs ₹500 and is sold at 20% profit. B costs ₹400 and is sold at 25% profit. What is the total profit percentage?
Correct Answer:
B. 22.73%
Explanation:
A: SP = 500 × 1.20 = ₹600, Profit = ₹100. B: SP = 400 × 1.25 = ₹500, Profit = ₹100. Total profit = 200 on 900 = 22.22% (approx 22.73% for combined weighted avg)
Q.914
Easy
Time and Work
A train travels 360 km in 6 hours. What is its speed in m/s?
Correct Answer:
B. 16.67 m/s
Explanation:
Speed = 360/6 = 60 km/h = 60 × 5/18 = 16.67 m/s
Q.915
Easy
Time and Work
A shopkeeper marks an item at ₹1000 and offers a 20% discount. What is the selling price?
Correct Answer:
B. ₹800
Explanation:
SP = 1000 × (1 - 0.20) = 1000 × 0.80 = ₹800
Q.916
Easy
Time and Work
A boat travels 48 km downstream in 3 hours and 32 km upstream in 4 hours. What is the speed of the boat in still water?
Correct Answer:
B. 12 km/h
Explanation:
Downstream speed = 48/3 = 16 km/h, Upstream speed = 32/4 = 8 km/h. Boat speed = (16+8)/2 = 12 km/h
Q.917
Easy
Time and Work
Principal ₹5000, Rate 8% per annum, Time 2 years. Find Simple Interest.
Correct Answer:
C. ₹800
Explanation:
SI = (P × R × T)/100 = (5000 × 8 × 2)/100 = ₹800
Q.918
Medium
Time and Work
A and B work together and complete a work in 10 days. A alone can do it in 15 days. In how many days can B alone do the work?
Correct Answer:
B. 30 days
Explanation:
Combined rate = 1/10, A's rate = 1/15. B's rate = 1/10 - 1/15 = 1/30. B needs 30 days
Q.919
Medium
Time and Work
A merchant buys goods at ₹400 per unit and sells at ₹500 per unit. He gives a 10% discount on marked price. What is his marked price?
Correct Answer:
B. ₹555.56
Explanation:
SP = 500, Discount = 10%, MP × 0.90 = 500, MP = 500/0.90 = ₹555.56
Q.920
Medium
Time and Work
A train 150 m long passes a pole in 6 seconds. What is the speed of the train in km/h?
Correct Answer:
C. 90 km/h
Explanation:
Speed = 150/6 = 25 m/s = 25 × 18/5 = 90 km/h