Govt. Exams
Entrance Exams
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Topics in Quantitative Aptitude
Pipe A can empty a full tank in 12 hours. Pipe B can fill the same tank in 18 hours. If both pipes are opened simultaneously with the tank full, how long to empty it?
Correct Answer:
B. 36 hours
EXPLANATION
Net rate = 1/12 - 1/18 = 3/36 - 2/36 = 1/36. Time = 36 hours.
A train 150m long crosses a pole in 15 seconds. What is its speed in km/h?
Correct Answer:
A. 36 km/h
EXPLANATION
Speed = 150/15 = 10 m/s = 10 × 3.6 = 36 km/h.
Two pipes A and B can fill a tank in 20 hours and 30 hours respectively. If both pipes are opened together, how long will it take to fill the tank?
Correct Answer:
B. 12 hours
EXPLANATION
Combined rate = 1/20 + 1/30 = 5/60 = 1/12. Time = 12 hours.
A shopkeeper marks goods at 40% above cost price. If he gives a discount of 25%, what is his profit percentage?
Correct Answer:
A. 5%
EXPLANATION
Let CP = 100. MP = 140. After 25% discount, SP = 140 × 0.75 = 105. Profit = 5%.
If the simple interest on Rs. 1000 for 2 years at rate R% per annum is Rs. 200, find the rate R.
Correct Answer:
C. 10%
EXPLANATION
SI = (P × R × T)/100. 200 = (1000 × R × 2)/100. R = 10%
A train 150m long takes 12 seconds to pass a pole. What is its speed in km/h?
Correct Answer:
B. 45 km/h
EXPLANATION
Speed = Distance/Time = 150/12 = 12.5 m/s = 12.5 × 3.6 = 45 km/h
If 30% of a number is 120, what is 25% of that number?
Correct Answer:
C. 100
EXPLANATION
Number = 120/0.30 = 400. 25% of 400 = 100
A boat travels 60 km downstream in 4 hours and 60 km upstream in 6 hours. What is the speed of the current?
Correct Answer:
A. 2.5 km/h
EXPLANATION
Downstream speed = 15 km/h, Upstream speed = 10 km/h. Current = (15-10)/2 = 2.5 km/h
Two pipes A and B can fill a tank in 10 hours and 15 hours respectively. If both pipes are opened together, in how many hours will the tank be filled?
Correct Answer:
B. 6 hours
EXPLANATION
Combined rate = 1/10 + 1/15 = 5/30 = 1/6. Time = 6 hours
A man travels 120 km in 8 hours. If he increases his speed by 25%, how much distance will he cover in 5 hours?
Correct Answer:
B. 93.75 km
EXPLANATION
Original speed = 120/8 = 15 km/h. New speed = 15 × 1.25 = 18.75 km/h. Distance in 5 hours = 18.75 × 5 = 93.75 km
