24
Q:

Which of the following statements is not correct?

A) log10 = 1 B) log (2 + 3) = log (2 x 3)
C) log1 = 0 D) log (1 + 2 + 3) = log 1 + log 2 + log 3

Answer:   B) log (2 + 3) = log (2 x 3)



Explanation:

log (2 + 3) = log 5

 

log (2 x 3) = log 2 + log 3

 


 log (2 + 3) log (2 x 3)

Q:

It is given that log10 2= 0.301 and log10 3 = 0.477. How many digits are there in (108)10?

A) 19 B) 20
C) 21 D) 22
 
Answer & Explanation Answer: C) 21

Explanation:
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45 5236
Q:

If 5x - 17 = -x + 7, then x = ?

A) 4 B) 5
C) 7 D) 9
 
Answer & Explanation Answer: A) 4

Explanation:

Given equation  5x-17 = -x+7

Add 1x to each side of the equation

5x-17+x = -x+7+x

6x=24

x=4

 

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18 2392
Q:

Solve the equation 122x+1 = 1 ?

A) -1/2 B) 1/2
C) 1 D) -1
 
Answer & Explanation Answer: A) -1/2

Explanation:

Rewrite equation as 122x+1 = 120

 

Leads to 2x + 1 = 0 

 

Solve for x : x = -1/2

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47 6296
Q:

If log72 = m, then log4928 is equal to ?

A) 1/(1+2m) B) (1+2m)/2
C) 2m/(2m+1) D) (2m+1)/2m
 
Answer & Explanation Answer: B) (1+2m)/2

Explanation:

log4928 = 12log77×4

 

= 12+122log72
= 12+log72
12 + m
1+2m2.

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65 12880
Q:

If a2+b2 = c2 , then 1logc+ab + 1logc-ab = ?

A) 1 B) 2
C) 4 D) 8
 
Answer & Explanation Answer: B) 2

Explanation:

Given a2 + b2 = c2

 

Now  1logc+ab  + 1logc-ab 

 

logbc+a + logbc-a

 

logbc2-a2

2logbb = 2

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48 10442
Q:

If log 64 = 1.8061, then the value of log 16 will be (approx)?

A) 1.9048 B) 1.2040
C) 0.9840 D) 1.4521
 
Answer & Explanation Answer: B) 1.2040

Explanation:

Given that, log 64 = 1.8061

 i.e log43=1.8061 

--> 3 log 4 = 1.8061

--> log 4 = 0.6020

--> 2 log 4 = 1.2040

log42=1.2040

Therefore, log 16 = 1.2040

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54 18184
Q:

A fast moving superfast express crosses another pasenger train in 20 seconds. The speed of faster train is 72 km/hr and speeds of slower train is 27 km/h. Also the length of faster ntrain is 100m, then find the length of the slower train if they are moving in the same direction.

A) 100 m B) 125 m
C) 150 m D) 175 m
 
Answer & Explanation Answer: C) 150 m

Explanation:

Time=Sum of length of the two trainsDifference in speeds

20=(100+x)252 

 X=150m

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46 8055
Q:

For xN, x>1,  and  p=logxx+1q=logx+1x+2 then which one of the following is correct?

A) p < q B) p = q
C) p > q D) can't be determined
 
Answer & Explanation Answer: C) p > q

Explanation:

kl>k+1l+1 for (k,l) > 0 and  k > l 

 

 

 

Let     k = x+1    and   l = x

 

 

 

Therefore, x+1x>(x+1)+1(x)+1

 

 

 

 (x + 1) > x

 

 

 

Therefore, log(x+1)log(x)>log(x+2)log(x+1)

 

 

 

logxx+1 >logx+1x+2

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40 5991