CGL MAINS 2015 : Quant Quiz



1.A man bought 20 dozen eggs for Rs. 720. What should be the selling price of each egg if he wants to make a profit of 20%? 
(1) Rs. 3.25  
(2) Rs. 3.30 
(3) Rs. 3.50 
(4) Rs. 3.60 

2.The value of equipment depreciates by 20% each year. How much less will the value of the equipment be after 3 years?  
(1) 48.8%  
(2) 51.2% 
(3) 54% 
(4) 60%

3.A's salary is 40% of B's salary and B‘s salary is 25% of C's salary. What percentage of C's salary is A's salary?
(1) 5%  
(2) 10% 
(3) 15% 
(4) 20%


4.In an examination, 93% of students passed and 259 failed. The total number of students appearing at the examination was 
(1) 3700   
(2) 3850 
(3) 3950 
(4) 4200

5.A and B together can complete a piece of work in 18 days, B and C in 24 days and A and C in 36 days. In how many days, will all of them together complete the work?
(1) 16  
(2) 15  
(3) 12 
(4) 10

6.A can complete 2/3 of a work in 4 days and B can complete 3/5 of the work in 6-clays. In how many days can both A and B together completes the work?
(1) 3  
(2) 2 
(3) 3 3/4  
(4) 2 7/8 

7.A tap can fill a cistern in 40 minutes and a second tap can empty the filled cistern in 60 minutes. By mistake without closing the second tap, the first tap was opened. In how many minutes will the empty cistern be filled ?
(1) 72  
(2) 84  
(3) 108   
(4) 120

8.A man goes from Mysore to Bangalore at a uniform speed of 40 km/hr and comes back to Mysore at a uniform speed of 60 km/hr. His average speed for the whole journey is 
(1) 48 km/ hr
(2) 50 km/hr
(3) 54 km/ hr
(4) 55 km/ hr 

9.A boat goes 12 km downstream and comes back to the starting point in 3 hours. If the speed of the current is 3 km/ hr, then the speed (in km/ hr) of the boat in still water is
(1) 12  
(2) 9  
(3) 8  
(4) 6

10.Two trains of lengths 70 m and 80 m are running at speeds of 68 km/hr and 40 km/hr respectively on parallel tracks in opposite directions. In how many seconds will they pass each other?
(1) 10  
(2) 8  
(3) 5  
(4) 3

ANSWERS AND SOLUTION
1.(4) CP of 1 egg = 720/(20 * 12) = Rs.3
so Required SP of 1 egg = 3×120/100 = Rs. 3.60

2.(1) If the present worth of the equipment be Rs. 100. Then
its price after 3 years
= 100 × (80/100)^3 = Rs. 51.2
so Description = 48.8%

3.(2) Let B's salary = Rs. 100
so C‘s salary = Rs. 400
and A's salary = Rs. 40
so Required percentage = 40/400 ×100 = 10%
 
4.(1) if the total number of students
be x, then
7% of x = 259
=> (x * 7)/100 = 259
=> x = (259 ×100)/7=3700

5.(1) (A+B)’s 1 day’s work = 1/18
(B +C)’s 1 day work = 1/24
(A + C)’s 1 day’s work = 1/36
Adding all three,
2(A + B+ C)’s 1 day’s work
= 1/18 + 1/24 + 1/36
= (4 +3 + 2)/72 = 1/8
so (A + B +C)’a 1 day’ s work = 1/16
so A, B and C together will complete the work in 16 days.
 
6.(3) Time taken by A to complete
The work = (4 * 3)/2 = 6 days
Time taken by B to complete the work = (6 * 5)/3 = 10 days
so (A +B)’s 1 day work
= 1/6 + 1/10 = (5 +3)/30 = 8/30 = 4/15
so A and B together will complete the work in 15/4 = 3 3/4 days.
 
7.(4)
Part of the cistern filled in 1 minute by both the taps
= 1/40 – 1/60 = ( 3 -2)/120 = 1/120
so Empty cistern will be filled in 120 minutes

8.(1)
Average speed
= (2xy)/(x+y) kmph
= (2 * 40 * 60)/(40 + 60)kmph
= 48kmph

9.(2)
If the speed of boat in still water be x kmph, then
12/(x + 3) + 12/(x -3) = 3
=> 12 (x – 3 + x + 3)/(x + 3) (x -3) = 3
=> 4 * 2x = x^2 – 9
=> x^2 – 8x – 9 = 0
=> x^2 – 9x + x – 9 = 0
=> x(x – 9) + 1 (x -9) = 0
=> (x -9) (x + 1) = 0
=> x = 9 becouse x ≠ -1
 
10.(3) Relative speed = (68 + 40) kmph
= 108 kmph
= (108 * 5)/18 m/sec. = 30 m/sec
so Required time = (Sum of the lengths of both trains)/(Relative speed)
= (70 + 80)/30 second
= 5 second
 

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