1. In how many different ways can the letters of the word "CANDIDATE" be arranged in such a way that the vowels always come together?
A. 4320
B. 1440
C. 720
D. 840
2. In how many different ways can the letters of the word "RADIUS" be arranged in such a way that the vowels occupy only the odd positions?
A. 72
B. 144
C. 532
D. 36
3. If 5:7 is the ratio of the present ages of Shahul and Ravi respectively. The difference between their ages is 6 years then what is the age of Shahul?
A. 15 years
B. 24 years
C. 17 years
D. 19 years
4. The ratio of present ages of Mani and Dilip is 4:3, after 3 years Mani's age will be 39 years then the present age of Dilip is :
A. 20 years
B. 27 years
C. 23 years
D. 25 years
5. The ratio of the age of Hari to that of Charan is 6:7. If Hari is 4 years younger than Charan then what will be the ratio of the ages of Hari and Charan after 4 years?
A. 7 : 8
B. 1 : 4
C. 2 : 5
D. 5 : 6
Answers and Explanations
1. Answer - Option A
Explanation -
There are 9 letters in the given word, out of which 4 are vowels.
In the word "CANDIDATE" we treat the vowels "AIAE" as one letter.
Thus, we have CNDDT(AIAE).
Now, we have to arrange 6 letters, out of which D occurs twice.
Therefore, number of ways of arranging these letters = [latex]\frac {6!}{2!} = \frac {720}{2} = 360[/latex] ways.
Now, AIAE has 4 letters, in which A occurs 2 times and the rest are different.
Number of ways of arranging these letters = [latex]\frac {4!}{2!} = \frac {1 x 2 x 3 x 4}{2} = 12[/latex]
Therefore, required number of words = (360 x 12) = 4320.
2. Answer - Option D
Explanation -
There are 6 different letters in the given word, out of which there are 3 vowels and 3 consonants.
Let us mark these positions as under:
[1] [2] [3] [4] [5] [6]
Now, 3 vowels can be placed at any of the three places out of 3 marked 1, 3 and 5.
Number of ways of arranging the vowels = [latex]^{3}{P}_{3} = 3! = 6[/latex] = 3! = 6 ways.
Also, the 3 consonants can be arranged at the remaining 3 positions.
Number of ways of these arrangements = [latex]^{3}{P}_{3} = 3! = 6[/latex] ways.
Therefore, total number of ways = 6 x 6 = 36.
3. Answer - Option A
Explanation -
Let the present age of Shahul and Ravi be 5X and 7X respectively.
Given that 7X - 5X = 6
2X = 6 [latex]\Rightarrow[/latex] X = 3
Then Shahul's present age is 5X = 5(3) = 15.
Hence, the answer is 15 years.
4. Answer - Option B
Explanation -
Let the present ages of Mani and Dilip is 4X and 3X respectively.
After 3 years Mani's age is 4X + 3
4X + 3 = 39
4X = 36
X = 9.
Then the present age of Dilip is 3X = 3(9) = 27
Hence the answer is 27 years.
5. Answer - Option A
Explanation -
Ratio of the ages of Hari and Charan is 6:7.
Let the ages of Hari and Charan be 6X years and 7X years respectively.
Then 7X - 6X = 4 (since Hari is 4 years younger)
X = 4.
Now, the required ratio is 6X + 4 : 7X + 4
6(4) + 4 : 7(4) + 4 = 28 : 32
7 : 8
Hence the answer is 7 : 8