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- Question
- There are 20 books of which 4 are single volumes and the other are books of 8, 5 and 3 volumes respectively. In how many ways can all these books be arranged on a self so that volumes of the same book are not separated?
Options- A. 7! 8! 5! 3!
- B. 7! 8! 4! 3!
- C. 7! 6! 5! 3!
- D. None of these
- Correct Answer
- 7! 8! 5! 3!
ExplanationVolumes of the same book are not to be separated i, e. all volumes of the same book are to be kept together, Regarding all volumes of the same book as one book, we have only 4 + 1 + 1 + 1 = 7 books.
These seven books can be arranged in 7! ways. The book having 8 volumes can be arranged among themselves in 8! ways, the book having 5 volumes can be arranged among themselves in 5! ways, and the book having 3 volumes can be arranged among themselves in 3! ways.
? Required number = 7! 8! 5! 3! - 1. How long will a sum of money invested at 5% per annum SI take to increase its value by 50%
Options- A. 10 yr
- B. 12 yr
- C. 15 yr
- D. 7 yr Discuss
- 2. The radius of a circle is so increased that its circumference increased by 5%. The area of the circle, then increases by
Options- A. 12.5%
- B. 10.25%
- C. 10.5 %
- D. 11.25% Discuss
- 3. In a class, there are 80 students and their average marks in the annual examination are 40. If the average marks of passed students are 60 and average marks of failed students are 35, then find out the number of students who failed.
Options- A. 63
- B. 60
- C. 72
- D. 64 Discuss
- 4. 2 men or 5 women or 7 boys can finish a work in 469 days, then the number of days taken by 7 men, 5 women and 2 boys to finish the work is :
Options- A. 134
- B. 106
- C. 100
- D. 98 Discuss
- 5. If the unit digit in the product 75? x 49 x 867 x 943 be 1, then the value of? is
Options- A. 1
- B. 3
- C. 7
- D. 9 Discuss
- 6. [(272 - 32) (124 + 176)] / (17 x 15 - 15) =?
Options- A. 0
- B. 2.25
- C. 300
- D. None of these Discuss
- 7. The average of 8, 9, 12, 13, 15, 9 is
Options- A. 11
- B. 6
- C. 16
- D. 18 Discuss
- 8. A train 110 metres in length travels at 60 km/hr.In what time will it pass a man which is walking against the train at 6 km an hour?
Options- A. 71/3 seconds
- B. 6 seconds
- C. 62/3 seconds
- D. Data inadequate Discuss
- 9. Four metal rods of lengths 78 cm, 104 cm, 117 cm and 169 cm are to be cut into parts of equal length. Each part must be as long as possible. What is the maximum number of pieces that can be cut?
Options- A. 27
- B. 36
- C. 43
- D. 480 Discuss
- 10. A train travelling at 30 km an hour took 13 1/ 2 sec in passing a certain point. Find the length of the train?
Options- A. 113 metres
- B. 112 metres
- C. 112.5 metres
- D. None of these Discuss
More questions
Correct Answer: 10 yr
Explanation:
Let sum be P.
? 50% of P = P/2 = SI
Now, P/2 = (P x 5 x T) / 100 [ as time = 10 yr]
? P/2 = 5PT / 100
? 1/2 = T/20
? = T = 10 yr
Correct Answer: 10.25%
Explanation:
Increase in circumference of circle = 5%
? Increase in radius is also 5%.
Now, increase in area of circle = 2a + (a2/100) %
Where, a = increase in radius= 2 x 5 + (5 x 5)/100 % = 10.25%
Correct Answer: 64
Explanation:
Let the number of failed student = Y
? Number of passed student = 80 - Y
sum of marks of all students = sum of marks of passed students + sum of marks of failed students
80 x 40 = (80 - Y) x 60 + 35Y
? 3200 =4800 - 60Y + 35Y
? 25Y = 1600
? Y = 64
? Number of students who failed = 64
Correct Answer: 98
Explanation:
2 men = 7 boys
? 1 man = 7/2 days
5 women = 7 boys
? 1 women = 7/5 boys
7 men + 5 women + 2 boys = 7 x 7/2 + 5 x 7/5 + 2 = 67/2 boys
Now, B1 x D1 = B2 x D2
7 X 469 = 67/2 x D2
D2 = 98 days
Correct Answer: 9
Explanation:
Let the value for ? be N
So N x 9 x 7 x 3 = a number with unit digit 1.
Clearly, the minimum value of N is 9.
Correct Answer: 300
Explanation:
Given expression = [(272 - 32) (124 + 176)] / (17 x 15 - 15)
= (240 x 300 ) / 240
= 300
Correct Answer: 11
Explanation:
Average = (8 + 9 + 12 + 13 + 15 + 9)/6
= 66 / 6
= 11
Correct Answer: 6 seconds
Explanation:
? Relative speed of the train = 60 + 6 = 66 km/hr
= 66 x 5/18 m/sec = 55/3 m/sec
? Required time = 110 x (3/55) = 6 sec
Correct Answer: 36
Explanation:
Given, length of four metal roads are 78, 104, 117 and 169 cm.
Now,
78 = 13 x 2 x 3,
104 = 13 x 2 x 2 x 2,
117 = 13 x 3 x 3,
169 = 13 x 13
Length of each piece of rod as long as possible, HCF = 13 CM
? Number of piece = 6 + 8 + 9 + 13 = 36
Correct Answer: 112.5 metres
Explanation:
Speed = 30 km/hr = 30 x (5/18) = 25/3 m/sec.
? Length of the train = (25/3) x (27/2)
= 225/2 = 1121/2 metres
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