Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q51.  A tank has leak which would empty the completely filled tank in 10 hours.If the tank is full of water and a tap is opened which admits 4 liters of water per minute in the tank, the leak takes 15 hours to empty the tank. How many liters of water does the tank hold ? 
1)  2400  2)  3600 
3)  4800  4)  7200 
5)  None of these 
Answer : 7200
Explanation : Let, the capacity of the tank be "X" liters.
Explanation : Let, the capacity of the tank be "X" liters.
According to the problem: 15 x (X/10  4 x 60) = X
Or X = 7200 liters
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Q52.  The batting average of 30 innings of a cricketer is 40 runs. His highest score exceeds his lowest score by 100 runs.If these two innings are not included, the average of the remaining 28 innings is 38. What is the lowest score of the player ? 
1)  12  2)  16 
3)  18  4)  20 
5)  None of these 
Answer : 18
Explanation : Let, the highest and lowest score are x and y respectively.
Explanation : Let, the highest and lowest score are x and y respectively.
So, x + y = (40 X 30 )  (28 X 38) = 136  (i)
Given, xy = 100  (ii)
Given, xy = 100
By solving, the above equation we get, x= 118 and x = 18
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Q53.  A vendor buy Fresh Fruits, contain 70% water and also buy Dry Fruits which contain 40% water. If he buys 120 kg of Fresh Fruits,how much quantity of Dry Fruits can be obtains from that quantity? 
1)  56 kg  2)  60 kg 
3)  64 kg  4)  72 kg 
5)  None of these 
Answer : 60 kg
Explanation : Given ,total quantity of fresh fruits = 120 kg
Explanation : Given ,total quantity of fresh fruits = 120 kg
In the fresh fruits , water contain = 120 x (70/100 ) = 84 kg and nonwater contain = 12084 = 36 kg.
In the Dry fruits, water contain = 40% and nonwater contain 60%.
Since, Nonwater quantity is always constant i.e.
60% = 36 kg
or 100% = (36/60) x 100 = 60 kg
Thus , Dry fruits quantity = 60 kg in 120 kg of Fresh fruits .
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Q54.  A shopkeeper marks up his goods by 50%. However, he could sell only onethird of his stock at this price. The half of the remaining stock was sold at a discount of 7.14% and remaining at a discount of 16.67%. What is the overall percentage profit of the trader ? 
1)  28%  2)  32% 
3)  36%  4)  38% 
5)  None of these 
Answer : 38%
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Q55.  If a  b = 9 and a^{2} + b^{2} = 125, the what should be the value of ab ? 
1)  16  2)  18 
3)  20  4)  22 
5)  None of these 
Answer : 22
Explanation :
Explanation :
First Method::
We know that, 2ab = (a^{2} + b^{2})  (a  b)^{2} = 125  81 = 44 or ab = 22.
Second Method:
We know that, (a  b)^{2} = a^{2} + b^{2} 2ab = 125 2ab or 81 = 125 2ab or 2ab = 12581 =44
or ab =44/2=22
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Q56.  A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct ? 
1)  2 p.m. on Tuesday  2)  1 p.m. on Friday 
3)  3 p.m. on Thursday  4)  2 p.m. on Wednesday 
5)  None of these 
Answer : 2 p.m. on Wednesday
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Q57. 

1)  12.5%  2)  17.5% 
3)  19%  4)  21% 
5)  None of these 
Answer : 19%
Explanation : Allegation Method:
Explanation : Allegation Method:
10% (C) x% (D)
15% (M)
(DM) = x15 (MC) = 15 10=5
So, x15 / 5 = 4/5
or x =15+4= 19%
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Q58. 

1)  288  2)  360 
3)  365  4)  435 
5)  None of these 
Answer : 365
Explanation : LCM of 6,8,9 and 10 is 360.
Explanation : LCM of 6,8,9 and 10 is 360.
So, total numbers of dozens of oranges are 360 +5 = 365
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Q59. 

1)  30  2)  31 
3)  32  4)  35 
5)  None of these 
Answer : 30
Explanation : HCF of 408 and 312 is 24.
Explanation : HCF of 408 and 312 is 24.
So, total numbers of sections = (408+312) /24 = 30
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Q60. 

1)  90 and 24  2)  120 and 24 
3)  120 and 54  4)  180 and 114 
5)  None of these 
Answer : 90 and 24
Explanation : The factors of 360 = 2 X 2 X 2 X 3 X 3 X 5
Explanation : The factors of 360 = 2 X 2 X 2 X 3 X 3 X 5
So, two numbers are 2 X 2 X 2 X 3 =24 and 2 X 3 X 3 X 5 = 90
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