2
Q:

If a, b, c be the terms of a GP then the value of (q-r) log a + (r-p) log b + (p-q) log c is :

A) 0 B) 1
C) -1 D) pqr

Answer:   A) 0

Explanation:

Let m be the first term and k be the common ratio of GP, then 

                             \inline a=mk^{p-1}

                             \inline b=mk^{q-1}

                             \inline c=mk^{r-1}

\therefore \inline (q-r)\log a + (r-p) \log b + (p-q) \log c = \log \left [ mk^{(p-1)} \right ]^{q-r}+\log \left [ mk^{(q-1)} \right ]^{r-p}+\log \left [ mk^{(r-1)} \right ]^{p-q}

       = \inline \log (m^{q-r+r-p+p-q})(k^{p-1})^{q-r}(k^{q-1})^{r-p}(k^{r-1})^{p-q}

       = \inline \log m^{0}k^{0}=\log 1=0

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:

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7 496
Q:

For  and  , 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:

 for (k,l) > 0 and  k > l

Let     k = x+1    and   l = x

 

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6 469
Q:

The Value of   is 

A) -1 B) 0
C) 1/2 D) 1
 
Answer & Explanation Answer: B) 0

Explanation:

                                                                 

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6 513
Q:

What is the number of digits in ? Given that log3 = 0.47712?

A) 12 B) 13
C) 14 D) 15
 
Answer & Explanation Answer: B) 13

Explanation:

 Let   

Then ,    

= 27 x 0.47712 = 12.88224

Since the characteristic in the resultant value of log x is 12

 The number of digits in x is (12 + 1) = 13

Hence the required number of digits in  is 13.

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4 541
Q:

Find value of 

A) 1/2 B) 3/2
C) 2 D) 2/3
 
Answer & Explanation Answer: B) 3/2

Explanation:

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5 521