Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q1.  A tank has three drain pipes, the first two pipes A and B operating simultaneously can empty the tank in half the time that of C, third pipe, alone takes to empty it. Pipe A working alone takes half the time taken by pipe B. Together they take to fill the tank in 6 hrs 40 mins. What is time taken for A to empty the tank alone ? 
1)  11hrs  2)  12 hrs 
3)  111/9hrs  4)  121/3hrs 
5)  None of these 
Answer : 111/9hrs
Explanation :
Explanation :
Let, C pipe takes x hrs ,then A pipe takes x/2 hrs
So, C pipe takes
=2(x+x/2) =3x hrs
Then, (A+B+C) pipes can
do in 1 hr = 1/x + 2/x +1/3x = 10/3x hrs
But given , total
time taken by all pipes = 6 hrs 40 min =
62/3 hrs = 20/3 hrs
So, 10/3x hrs = 3/20
Or x =200/9 hrs i.e time
taken for pipe B
Therefore, time taken
for pipe A = (200/9)/2 = 100/9 = 111/9hrs
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Q2. 

1)  8hrs  2)  10hrs 
3)  12hrs  4)  14hrs 
5)  None of these 
Answer : 14hrs
Explanation :
Explanation :
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Q3. 

1)  2 hour  2)  3 hour 
3)  4 hour  4)  6 hour 
5)  None of these 
Answer : 6 hour
Explanation :
Explanation :
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Q4. 

1)  80 gallons  2)  120 gallons 
3)  140 gallons  4)  160 gallons 
5)  None of these 
Answer : 120 gallons
Explanation :
Explanation :
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Q5. 

1)  81 min.  2)  108 min. 
3)  144 min.  4)  164 min. 
5)  None of thesae 
Answer : 144 min.
Explanation : Let, the slower pipe alone will fill the tank in x minutes.
Explanation : Let, the slower pipe alone will fill the tank in x minutes.
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Q6. 

1)  15 min., 20 min  2)  15 min, 10 min 
3)  10 min, 15 min  4)  25 min, 20 min 
5)  None of these 
Answer : 10 min, 15 min
Explanation :
Explanation :
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Q7. 

1)  7.5 hours  2)  8 hours 
3)  8.5 hours  4)  12 hours 
5)  None of these 
Answer : 7.5 hours
Explanation : Work done by all the tanks working together in 1 hour.
Explanation : Work done by all the tanks working together in 1 hour.
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Q8. 

1)  12 hour  2)  15 hour 
3)  24 hour  4)  30 hour 
5)  None of these 
Answer : 30 hour
Explanation :
Explanation :
Let, the leak empties the tank in x hours.
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Q9.  A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. What is time for the first pipe to fill up the tank alone ? 
1)  10hrs  2)  12hrs 
3)  15hrs  4)  18hrs 
5)  None of these 
Answer : 15hrs
Explanation :
Explanation :
Let, the first pipe can alone takes x hours to fill the tank .
Then, second and third pipes will take (x 5) and (x  9) hours respectively .
Then, second and third pipes will take (x 5) and (x  9) hours respectively .
So,(1/x) + (1/x5) = 1/x9.
Solving,we get x =15
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Q10. 

1)  12 min 15 sec  2)  15 min 30 sec 
3)  20 min 10 sec  4)  25 min 20 sec 
5)  None of these 
Answer : 25 min 20 sec
Explanation :
Explanation :
Given, the tank
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