What is the value of log7777 = ? from Mathematics

Subject

Mathematics

Class

NDA Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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1.

What is the value of log7777 = ?

  • 3log27

  • 1 - 3log27

  • 1 - 3log72

  • 78


C.

1 - 3log72

777  = 723 - 123 = 778 log7log7777  = log7log7778= log778log77= log778= log77 - log78= 1 - log723= 1 - 3log72


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2.

If an infinite GP has the first term x and the sum 5, then which of the following is correct ?

  • x < - 10

  •  - 10 < x < 0

  • 0  < x < 10

  • x > 10


3.

Consider the following expressions :

1. x + x2 - 1x2. ax2 + bx + x - c + dx - ex23. 3x2 - 5x +ab4. 2x2 - ax + b35. 1x - 2x+ 5Which of the above are rational expression ?

  • 1, 4 and 5 only

  • 1, 3, 4 and 5 only

  • 2, 4 and 5 only

  • 1 and 2 only


4.

A square matrix A is called orthogonal if

  • A = A2

  • A' = A - 1

  • A = A - 1

  • A = A'


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5.

If A, B and C are subsets of a Universal set, then which one of the following is not correct ?

  • A  B  C = A  B  A  C

  • A'  A  B = B'  A'  A

  • A'  B  C = C'  B'  A'

  • A  B  C = A  C  B  C


6.

Let x be the number of integers lying between 2999 and 8001 which have at least two digits equal. Then x is equal to

  • 2480

  • 2481

  • 2482

  • 2483


7.

The sum of the series 3 - 1 + 13 - 19 + ... = 

  • 209

  • 920

  • 94

  • 49


8.

A survey was conducted among 300 students. It was found that 125 students like to play cricket, 145 students like toplay football and 90 students like to play tennis. 32 students like to play exactly two games out of the three games.

How many students like to play all the three games ?

  • 14

  • 21

  • 28

  • 35


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9.

A survey was conducted among 300 students. It was found that 125 students like to play cricket, 145 students like toplay football and 90 students like to play tennis. 32 students like to play exactly two games out of the three games. How many students like to play exactly only one game?

How many students like to play all the three games ?

  • 196

  • 228

  • 254

  • 268


10.

If α and β(  0) are the roots of the quadratic equation x2 + αx - B = 0, then  the quadratic expression -x2 + αx + β  where x  R has

  • Least value - 14

  • Least value - 94

  • Greatest value 14

  • Greatest value  94


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