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1.
If log(k2 – 4k + 5) = 0, then the value of k is
  • A.
    0
  • C.
    2
  • B.
    1
  • D.
    3
  • Answer & Explanation
  • Report
Answer : [C]
Explanation :
log(K2 - 4K + 5) = 0
log(K2 - 4K + 5) = log1 (   log 1 = 0)  
 
 
  K2 - 4K + 5 = 1
 
  K2 - 4K + 4 = 0    
 
(K - 2)2 = 0     K = 2  
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2.
Log xy = 100 and logx2 = 10, then the value of y is
  • A.
    210
  • C.
    21000
  • B.
    2100
  • D.
    210000
  • Answer & Explanation
  • Report
Answer : [C]
Explanation :
logx2 = 10     x = 210
logxy = 100     y = x100 = (210)100 = 21000
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3.
The characteristic of the logarithm 332.6 is
  • A.
    3
  • C.
    2
  • B.
    4
  • D.
    1
  • Answer & Explanation
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Answer : [C]
Explanation :
Characteristic = 3 -1 = 2
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4.
If log4 log2 log3 (2x – 1) =
1
2
, find x
  • A.
    82
  • C.
    51
  • B.
    41
  • D.
    62
  • Answer & Explanation
  • Report
Answer : [B]
Explanation :
Log4 log2 log3 (2x - 1) =
1
2
 
 
  log2 log3 (2x - 1) = 41/2 = 2      
 
 
  log3 (2x - 1) = 22 = 4      
 
2x - 1 = 34 = 81
2x = 82
x = 41
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5.
If logab =
1
2
, logbc =
1
3
 and logca =
k
5
, the value of k is  
  • A.
    25
  • C.
    30
  • B.
    35
  • D.
    20
  • Answer & Explanation
  • Report
Answer : [C]
Explanation :
logab =
log b
log a
, logbc =
log c
log b
, logca =
log a
log c
 
 
  logab x logbc x logca =
log b
log a
x
log c
log b
x
log a
log c
=
1
2
x
1
3
x
k
5
 
 
 
  1 =
k
30
 
 
 
  k = 30  
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