Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q561. 

1)  2 hours  2)  3 hours 
3)  4 hours  4)  5 hours 
5)  None of these 
Answer : 4 hours
Explanation :
Explanation :
Speed downstream = (13 + 4) km/hr = 17 km/hr.
Time taken to travel 68 km downstream = ( 68/17) hrs = 4 hrs.
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Q562. 

1)  20 km/hr  2)  22 km/hr 
3)  24 km/hr  4)  28 km/hr 
5)  None of these 
Answer : 22 km/hr
Explanation :
Explanation :
Let the speed of the man in still water be x km/hr. then,
km/hr.
10/(x2) + 10/(x+2) = 55/60
or x = 22 km/hr
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Q563. 

1)  17 kg  2)  20 kg 
3)  26 kg  4)  31 kg 
5)  None of these 
Answer : 31 kg
Explanation :
Explanation :
Let A, B, C represent their respective weights. Then, we have:
A + B + C = (45 x 3) = 135 .... (i)
A + B = (40 x 2) = 80 .... (ii)
B + C = (43 x 2) = 86 ....(iii)
Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)
Subtracting (i) from (iv), we get : B = 31.
B's weight = 31 kg.
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Q564. 

1)  3500  2)  4000 
3)  4050  4)  5000 
5)  None of these 
Answer : 4000
Explanation :
Explanation :
Let P, Q and R represent their respective monthly incomes. Then, we have:
P + Q = (5050 x 2) = 10100 .... (i)
Q + R = (6250 x 2) = 12500 .... (ii)
P + R = (5200 x 2) = 10400 .... (iii)
Adding (i), (ii) and (iii), we get: 2(P + Q + R) = 33000 or P + Q + R = 16500 .... (iv)
Subtracting (ii) from (iv), we get P = 4000.
P's monthly income = Rs. 4000.
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Q565. 

1)  3500  2)  4000 
3)  4050  4)  5000 
5)  None of these 
Answer : 4000
Explanation :
Explanation :
Let P, Q and R represent their respective monthly incomes. Then, we have:
P + Q = (5050 x 2) = 10100 .... (i)
Q + R = (6250 x 2) = 12500 .... (ii)
P + R = (5200 x 2) = 10400 .... (iii)
Adding (i), (ii) and (iii), we get: 2(P + Q + R) = 33000 or P + Q + R = 16500 .... (iv)
Subtracting (ii) from (iv), we get P = 4000.
P's monthly income = Rs. 4000.
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Q566. 

1)  23 years  2)  24 years 
3)  25 years  4)  30 years 
5)  None of these 
Answer : 23 years
Explanation :
Explanation :
Let the average age of the whole team by x years.
Then,11x  (26 + 29) = 9(x 1)
or 11x  9x = 46
or 2x = 46
or x = 23.
So, average age of the team is 23 years.
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Q567. 

1)  76 kg  2)  76.5 kg 
3)  85 kg  4)  Data Inadequate 
5)  None of these 
Answer : 85 kg
Explanation :
Explanation :
Total weight increased = (8 x 2.5) kg = 20 kg.
So,weight of new person = (65 + 20) kg = 85 kg.
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Q568. 

1)  35 years  2)  40 years 
3)  50 years  4)  Data Inadequate 
5)  None of these 
Answer : 40 years
Explanation :
Explanation :
Sum of the present ages of husband, wife and child = (27 x 3 + 3 x 3) years = 90 years.
Sum of the present ages of wife and child = (20 x 2 + 5 x 2) years = 50 years.
Husband's present age = (90  50) years = 40 years.
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Q569. 

1)  34  2)  31 
3)  36  4)  32 
5)  None of these 
Answer : 36
Explanation :
Explanation :
Let the batsman’s average runs up to 12th innings was x.
Total run = 12 x.
Now total run up to 13th innings = (12 x + 96)
According to equation = (12 x + 96)/13 = x + 5 or x = 31.
So, after 13th innings average will be 31 + 5 = 36.
Shortcut Method :
96  (135) + 5 = 36
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Q570. 

1)  500  2)  600 
3)  550  4)  480 
5)  None of these 
Answer : 550
Explanation :
Explanation :
By alligantion method :
12000 3750
6000
6000  3750 = 2250 12000  6000 = 6000
So, final ratio = 2250 : 6000 = 3 : 8
So,total number of employees = (150/3) x 11 = 550
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