Mathmetics

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

Q1.
If x=2015, y=2014 and 2013 , then x2+y2+z2 -xy-yz-zx = ?
1) 2 2) 3
3) 4 4) 6
5)None of these
Answer : 3
Explanation : ATQ: x2+y2+z2 -xy-yz-zx
= x2-xy+y2 -yz+z2-zx 
x(x-y) + y((y-z) + z(z-x)
= 2015(2015-2014) + 2014(2014-2013)+2013(2013-2015)
= 2015 + 2014 + 4026
=4029-4026 =3

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Q2.
1) 8 2) 9
3) 10 4) 12
5)None of these
Answer : 10
Explanation :
Given, x2 + 9/x = 6x
Or x2 - 6x = 9
Or (x-3)2 = 0  
Or x = 3
So, x2 + 9/x= 10
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Q3.
If  a = 4/3, then, what is the value of 27a3 -108a+ 144a - 317  ?
1) 221 2) -231
3) -253 4) 0
5)None of these
Answer : -253
Explanation :
Given, a = 4/3
Or  3a = 4 
Or 3a - 4 = 0
Or (3a-4)3 = 27a3 - 108a2 + 144a - 64 = 03
Or 27a3 - 108a2 + 144a - 317 = (27a3 - 108a2 + 144a -64) - 153 = 0 - 253 = - 253
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Q4.
1) 0 2) 1
3) 2 4) 3
5)None of these
Answer : 3
Explanation :
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Q5.
 
1) 21 2) 23
3) 25 4) 27
5)None of these
Answer : 23
Explanation : We  know that,       
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Q6.
1) 1 2) 2
3) 4 4) 5
5)None of these
Answer : None of these
Explanation :
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