Sail E0 Webinar

Quantitative Aptitude

LOGARITHM MCQs

Logarithms

Total Questions : 289 | Page 24 of 29 pages
Question 231.


If ax = by, then:

  1.     log a = x b y
  2.     log a = x log b y
  3.     log a = y log b x
  4.    None of these
 Discuss Question
Answer: Option C. -> log a = y log b x

ax = by


If Ax = By, Then: log ax = log by


If Ax = By, Then: x log a = y log b



If Ax = By, Then:
log a
=
y
.
log b
x


Question 232.


If logx y = 100 and log2 x = 10, then the value of y is:

  1.    210
  2.    2100
  3.    21000
  4.    210000
 Discuss Question
Answer: Option C. -> 21000

log 2 x = 10     If Logx Y = 100 And Log2 X = 10, Then The Value Of Y Is:     x = 210.


If Logx Y = 100 And Log2 X = 10, Then The Value Of Y Is: logx y = 100


If Logx Y = 100 And Log2 X = 10, Then The Value Of Y Is: y = x100


If Logx Y = 100 And Log2 X = 10, Then The Value Of Y Is: y = (210)100     [put value of x]


If Logx Y = 100 And Log2 X = 10, Then The Value Of Y Is: y = 21000.


Question 233.

Which of the following statements is not correct?

  1.    log10 10 = 1
  2.    log (2 + 3) = log (2 x 3)
  3.    log10 1 = 0
  4.    log (1 + 2 + 3) = log 1 + log 2 + log 3
 Discuss Question
Answer: Option B. -> log (2 + 3) = log (2 x 3)

(a) Since loga a = 1, so log10 10 = 1.


(b) log (2 + 3) = log 5 and log (2 x 3) = log 6 = log 2 + log 3


     Which Of The Following Statements Is Not Correct? log (2 + 3) Which Of The Following Statements Is Not Correct? log (2 x 3)


(c) Since loga 1 = 0, so log10 1 = 0.


(d) log (1 + 2 + 3) = log 6 = log (1 x 2 x 3) = log 1 + log 2 + log 3.


So, (b) is incorrect.

Question 234.


If log 27 = 1.431, then the value of log 9 is:

  1.    0.934
  2.    0.945
  3.    0.954
  4.    0.958
 Discuss Question
Answer: Option C. -> 0.954

log 27 = 1.431


If Log 27 = 1.431, Then The Value Of Log 9 Is: log (33 ) = 1.431


If Log 27 = 1.431, Then The Value Of Log 9 Is: 3 log 3 = 1.431


If Log 27 = 1.431, Then The Value Of Log 9 Is: log 3 = 0.477


If Log 27 = 1.431, Then The Value Of Log 9 Is: log 9 = log(32 ) = 2 log 3 = (2 x 0.477) = 0.954.


Question 235.


If log
a
+
log
b
= log (a + b), then:
b
a

  1.    a + b = 1
  2.    a - b = 1
  3.    a = b
  4.    a2 - b2 = 1
 Discuss Question
Answer: Option A. -> a + b = 1


log
a
+ log
b
= log (a + b)
b
a



If Loga+logb= Log (a + B), Then:ba log (a + b) = log
If Loga+logb= Log (a + B), Then:ba
a
x
b
If Loga+logb= Log (a + B), Then:ba
= log 1.
b
a


So, a + b = 1.

Question 236.


log 8
is equal to:
log 8

  1.     1 8
  2.     1 4
  3.     1 2
  4.     1 8
 Discuss Question
Answer: Option C. -> 1 2

log 8
=
log (8)1/2
=
Log 8is Equal To:log 8log 8
=
1
.
log 8
log 8
log 8
2
Question 237.


If log 2 = 0.3010 and log 3 = 0.4771, the value of log5 512 is:

  1.    2.870
  2.    2.967
  3.    3.876
  4.    3.912
 Discuss Question
Answer: Option C. -> 3.876

log5 512
=
log 512
log 5
=
log 29
log (10/2)
=
9 log 2
log 10 - log 2
=
(9 x 0.3010)
1 - 0.3010
=
2.709
0.699
=
2709
699
= 3.876
Question 238.


If log10 2 = 0.3010, then log2 10 is equal to:

  1.     699 301
  2.     1000 301
  3.    0.3010
  4.    0.6990
 Discuss Question
Answer: Option B. -> 1000 301

log2 10 =
1
=
1
=
10000
=
1000
.
log10 2
0.3010
3010
301
Question 239.


If log10 7 = a, then log10
If Log10 7 = A, Then Log101is Equal To:70
1
If Log10 7 = A, Then Log101is Equal To:70
is equal to:
70

  1.    - (1 + a)
  2.    (1 + a)-1
  3.     a 10
  4.     1 10a
 Discuss Question
Answer: Option A. -> - (1 + a)

log10
If Log10 7 = A, Then Log101is Equal To:70
1
If Log10 7 = A, Then Log101is Equal To:70
70
= log10 1 - log10 70
= - log10 (7 x 10)
= - (log10 7 + log10 10)
= - (a + 1).
Question 240.

If log10 2 = 0.3010, the value of log10 80 is:

  1.    1.6020
  2.    1.9030
  3.    3.9030
  4.    None of these
 Discuss Question
Answer: Option B. -> 1.9030

log10 80
= log10 (8 x 10)
= log10 8 + log10 10
= log10 (23 ) + 1
= 3 log10 2 + 1
= (3 x 0.3010) + 1
= 1.9030.

Latest Videos
Chapter 1 - GLOBAL STEEL SCENARIO & INDIAN STEEL INDUSTRY Part 1 : (13-04-2024) INDUSTRY AND COMPANY AWARENESS (ICA)
Direction Sense Test Part 1 Reasoning (Hindi)
Chapter 1 - RMHP / OHP / OB & BP Part 1 : (14-02-2024) GPOE
Cube & Cuboid Part 1 Reasoning (Hindi)
Data Interpretation (DI) Basic Concept Reasoning (Hindi)
Counting Figures Part 1 Counting Of Straight Lines Reasoning (Hindi)
Sail E0 free webinar Webinars
Real Numbers Part 7 Class 10 Maths
Real Numbers Part 1 Class 10 Maths
Polynomials Part 1 Class 10 Maths

Latest Test Papers

DSP Combined 1 Free Revision Test SAIL JO E-0
GPOE / GPA Combined 1 Free Revision Test SAIL JO E-0
BSP Plant Specific Review Test SAIL JO E-0
BSL Combined 1 Free Revision Test SAIL JO E-0
GFM Combined 1 Free Revision Test SAIL JO E-0