Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q1.  The ratio between A's and Bs salary was 3:4,two year ago . The ratio's of individual salaries of A and B two year's ago and this year's salaries are 4:5 and 2:3 respectively. At present the total of their salary is Rs.4290. What is present salary of A ? 
1)  Rs.1560  2)  Rs.1600 
3)  Rs.1650  4)  Rs.1840 
5)  None of these 
Answer : Rs.1650
Explanation :
Explanation :
Let, two year ago ,the ratio of between A'and B's salary was 3x: 4x respectively.
The ratio of their individual salary between two years ago and this year is 4y:5y and 2z:3z respectively.
So, 4y = 3x (A's last year salary)
or y = .75x and 2z = 4x (B's last year salary)
or z = 2x
Now, the total of their salary is Rs.4290 .
So, 5y + 3z = Rs.4290
Replace y with .75x; replace z with 2x
So, 5(.75x) + 3(2x) = 4290
or 3.75x + 6x = Rs.4290 or 9.75x = 4290
or x = 4290/9.75 = 440
Then, A's present salary 3.75 (440) = Rs.1650
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Q2. 

1)  3 : 2  2)  2 : 1 
3)  3 : 1  4)  4 : 3 
5)  None of these 
Answer : 2 : 1
Explanation :
Explanation :
Let, the number be ‘x’ and ‘y’
So, (x+y)/(xy) = 3/1
or x + y = 3x  3y
or 2x = 4y
or x:y = 2:1
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Q3.  Two numbers are such that their difference, their sum and their product are in the ratio 1:7:24 respectively. What is the product of the two numbers ? 
1)  12  2)  24 
3)  36  4)  48 
5)  None of these 
Answer : 48
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Q4.  The income of A,B and C together is Rs.14500 and they spend 60%,65% and 70% of their income respectively. If their savings are in the ratio 14:21:15 . What is the income of B ? 
1)  Rs.4000  2)  Rs.4800 
3)  Rs.5600  4)  Rs.6000 
5)  None of these 
Answer : Rs.6000
Explanation : We know that, income  expenditure = saving
Explanation : We know that, income  expenditure = saving
Let, their income are 100% individually.
So, A's saving = 100  60= 40% ; B's saving = 100  65= 35% ; C's saving = 100  70= 30%
But their saving ratio are 14:21:15.
Then, A's income , 40% = 14 or 100% =( 14/40) x 100 = 35
B's income , 35% = 21 or 100% =( 21/35) x 100 = 60
C's income , 30% = 15 or 100% =( 15/30) x 100 = 50
So, 35x + 60x + 50x = Rs.14500
or 145x = Rs.14500
or x = 100
Therefore income of B= 100x60 = Rs.6000.
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Q5. 

1)  5 : 7  2)  3 : 7 
3)  7 : 5  4)  7 : 8 
5)  None of these 
Answer : 7 : 5
Explanation :
Explanation :
You see in first alloy the ratio is 7:2 and in alloy is 7:11.
So, let total in first alloy is 9kg and total in second alloy is ,18kg.
To equalise both, we LCM of both i.e. should be 18 kg.
Now,gold 14 and copper 4 kg in first , gold 7 and copper 11kg in second alloy.
Now, mix gold to gold and copper to copper.
14+7=21
And 4+11=15
So. Ratio is 21:15=7:5
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Q6. 

1)  72 litres.  2)  81 litres 
3)  121 litres  4)  144 litres 
5)  None of these 
Answer : 81 litres
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Q7. 

1)  3 : 5  2)  5 : 7 
3)  5 : 3  4)  7 : 5 
5)  None of these 
Answer : 3 : 5
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Q8. 

1)  Rs. 4000  2)  Rs. 4800 
3)  Rs. 5000  4)  Can't be determined 
5)  None of these 
Answer : Can't be determined
Explanation : Let, the amount of P, Q and R are 5x, 8x and 12x respectively.
Explanation : Let, the amount of P, Q and R are 5x, 8x and 12x respectively.
So, 8x +12x = 4 (5x)
Or 20x = 20x
Hence,we can not find their numerical values.
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Q9. 

1)  1 litres  2)  2 litres 
3)  3 litres  4)  4 litres 
5)  Non e of these 
Answer : 2 litres
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Q10. 

1)  20  2)  30 
3)  48  4)  58 
5)  None of these 
Answer : 30
Explanation :
Explanation :
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