In a certain laboratory, chemicals are identified by a colour-coding system. There are 20 different chemicals. Each one is coded with either a single colour or a unique two-colour pair. If the order of colours in the pairs does not matter, what is the minimum number of different colours needed to code all 20 chemicals with either a single colour or a unique pair of colours

1.  7

2.  6

3.  5

4.  8

View Answer  
4
Correct Answer :

6


Explanation :
No Explanation available for this question

Six boxes are numbered 1,2,3,4,5 and 6. Each box must contain either a white ball or a black ball. At least one box must contain a black ball and boxes containing black balls must be consecutively numbered. find the total number of ways of placing the balls.

1.  15

2.  20

3.  21

4.  36

View Answer  
4
Correct Answer :

21


Explanation :
No Explanation available for this question

In how many ways can 6 green toys and 6 red toys be arranged, such that 2 particular red toys are never together whereas 2 particular green toys are always together

1.  11! × 2!

2.  9! × 90

3.  4 × 10!

4.  18 × 10!

View Answer  
4
Correct Answer :

18 × 10!


Explanation :
No Explanation available for this question

The number of ways which a mixed double tennis game can be arranged amongst 9 married couples if no husband and wife play in the same is:

1.  1514

2.  1512

3.  3024

4.  3028

View Answer  
4
Correct Answer :

1512


Explanation :
No Explanation available for this question

Ten coins are tossed simultaneously. In how many of the outcomes will the third coin turn up a head

1.  210

2.  29

3.  3×28

4.  None of these

View Answer  
4
Correct Answer :

29


Explanation :
No Explanation available for this question

There are 5 Rock songs, 6 Carnatic songs and 3 Indi pop songs. How many different albums can be formed using the above repertoire if the albums should contain at least 1 Rock song and 1 Carnatic song

1.  15624

2.  16384

3.  6144

4.  240

View Answer  
4
Correct Answer :

15624


Explanation :
No Explanation available for this question

A book-shelf can accommodate 6 books from left to right. If 10 identical books on each of the languages A,B,C and D are available, In how many ways can the book shelf be filled such that book on the same languages are not put adjacently

1.  40P6 / 6!

2.  10×95

3.  6P4 / 2!

4.  4×35

View Answer  
4
Correct Answer :

4×35


Explanation :
No Explanation available for this question

In how many ways can the letters of the word ABACUS be rearranged such that the vowels always appear together

1.  

2.  3!×3!

3.  

4.  

5.  

View Answer  
5
Correct Answer :


Explanation :
No Explanation available for this question

If the letters of the word SACHIN are arranged in all possible ways and these words are written out as in dictionary, then the word ‘SACHIN’ appears at serial number:

1.  601

2.  600

3.  603

4.  602

View Answer  
4
Correct Answer :

601


Explanation :
No Explanation available for this question

In how many ways can 3 men and their wives be made stand in a line such that none of the 3 men stand in a position that is ahead of his wife

1.  

2.  

3.  

4.  

View Answer  
4
Correct Answer :


Explanation :
No Explanation available for this question
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