Time and Work
A shopkeeper marks an item at ₹1000 and offers a 20% discount. What is the selling price?
A
₹750
B
₹800
C
₹850
D
₹900
Explanation:
SP = 1000 × (1 - 0.20) = 1000 × 0.80 = ₹800
A train travels 360 km in 6 hours. What is its speed in m/s?
A
12 m/s
B
16.67 m/s
C
18 m/s
D
15 m/s
Correct Answer:
B. 16.67 m/s
Explanation:
Speed = 360/6 = 60 km/h = 60 × 5/18 = 16.67 m/s
A costs ₹500 and is sold at 20% profit. B costs ₹400 and is sold at 25% profit. What is the total profit percentage?
A
22.22%
B
22.73%
C
23%
D
21.5%
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)
If 24 workers can build a wall in 16 days, how many workers are needed to build the same wall in 12 days?
A
28 workers
B
30 workers
C
32 workers
D
36 workers
Correct Answer:
C. 32 workers
Explanation:
Total work = 24 × 16 = 384 worker-days. For 12 days: 384/12 = 32 workers
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?
A
45 hours
B
60 hours
C
50 hours
D
55 hours
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
A can complete a work in 12 days and B can complete the same work in 18 days. If they work together, in how many days will they complete the work?
A
7.2 days
B
7.5 days
C
8 days
D
6.5 days
Correct Answer:
A. 7.2 days
Explanation:
A's work per day = 1/12, B's work per day = 1/18. Combined = 1/12 + 1/18 = 5/36. Time = 36/5 = 7.2 days
Q.37
Medium
A mixture contains milk and water in ratio 5:3. If 8 liters of water is added, ratio becomes 5:4. Find the original quantity of milk.
A
40 liters
B
50 liters
C
60 liters
D
80 liters
Correct Answer:
A. 40 liters
Explanation:
Let milk = 5x, water = 3x. After adding 8 liters water: 5x/(3x+8) = 5/4. 20x = 15x + 40. 5x = 40. x = 8. Milk = 40 liters.
A person walks at 4 km/h for 2 hours, then at 5 km/h for 3 hours. What is the average speed?
A
4.4 km/h
B
4.5 km/h
C
4.6 km/h
D
4.8 km/h
Correct Answer:
A. 4.4 km/h
Explanation:
Total distance = 4×2 + 5×3 = 8 + 15 = 23 km. Total time = 5 hours. Average speed = 23/5 = 4.6 km/h. Option C is correct, not A.
Q.39
Medium
A clock gains 5 minutes every 12 hours. If it is set correct at 12 PM on Monday, what will it show at 12 PM on Tuesday?
A
12:10 PM
B
12:05 PM
C
12:15 PM
D
12:20 PM
Correct Answer:
A. 12:10 PM
Explanation:
In 12 hours, clock gains 5 minutes. In 24 hours, it gains 10 minutes. So at 12 PM Tuesday, clock will show 12:10 PM.
Q.40
Medium
A lost 10% by selling an item for ₹900. If he wants 15% profit, what should be the selling price?
A
₹1150
B
₹1200
C
₹1250
D
₹1320
Explanation:
SP = 900 is 90% of CP. So CP = 900/0.9 = 1000. For 15% profit, SP = 1000 × 1.15 = 1150.
