Demo questions for SI exam

Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exams https://telanganatoday.com/preparation-tips-to-crack-the-for-si-exams. Here are some subject-wise practice questions and answers along with explanations. Average 1. In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in […]

Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exams https://telanganatoday.com/preparation-tips-to-crack-the-for-si-exams.

Here are some subject-wise practice questions and answers along with explanations.

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Average
1. In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in the remaining 40 overs to reach the target of 282 runs?
a) 6.25 b) 5.5 c) 5 d) 4.75 e) None of these

2. The average of five numbers is 27. If one number is excluded, the average becomes 25. What is the excluded number?
a) 40 b) 37 c) 35 d) 30 e) 28.5

3. The average expenditure of 9 friends out of 10 is Rs 20. The tenth friend expenditure is Rs 45 more than the average expenditure of all 10 friends. Find the total expenditure of all 10 friends?
a) Rs 245 b)Rs 250 c)Rs 255 d) 260 e) Cannot be determined

4. The average salary of all the 100 workers in a workshop is Rs.24,000. The average salary of technicians is Rs.40,000 and the average salary of the rest is Rs.20,000. How many technicians are there in the workshop?
a) 10 b) 15 c) 18 d) 20 e) 26

5. Average weight of 20 people increased by 1.5 kg when one person of 50 kg is replaced by a new man. Then find the weight of the new man?
a) 51 kg b) 60 kg c) 70 kg d) 75 kg e) 80 kg

6. The average weight of A and B is 50 kg; B and C is 70 kg and C and A is 60 kg. Then find the weight of B
a) 40 kg b) 55 kg c) 58 kg d) 60 kg e) Cannot be determined

7. Find the average of 1, 4, 9, 16, ………625.
a)313 b) 221 c) 216 d) 208 e) None of these

Key

1. a
Runs scored in the first 10 overs = 10×3.2=32
Total runs = 282
remaining runs to be scored = 282 – 32 = 250
remaining overs = 40
Run rate needed = = 6.25

2. c
Sum of 5 numbers = 5×27 = 135
Sum of 4 numbers after excluding one number = 4×25 = 100
Excluded number = 135 – 100 = 35

3. b
Let average expenditure of 10 friends = x
Tenth friend expenditure = x 45
Total expenditure of ten friends = 10x = 9 X 20 x 45
9x = 225
x = 25
Total expenditure of ten friends = 10x = 10 X 25 = Rs 250

4. d
Let number of technicians = x
Number of other workers = 100 – x
Total salary = 100 X 24,000 = x X 40,000 (100 – x) 20,000
40,000x – 20,000x = 4,00,000
20,000x = 4,00,000
x = 20
Number of technicians = 20

5. e
Total increased weight = 20 X 1.5 = 30 kg
Weight of new person = 50 30 = 80 kg

6. d
The total weight of A and B = 2 X 50 = 100 kg
The total weight of B and C = 2 X 70 = 140 kg
The total weight of C and A = 2 X 60 = 120 kg
2(A B C) = 80 120 160 = 360
A B C = 180 kg
B’s weight = 180 – 120 = 60kg

7. b
The average of squares of first n natural numbers =
a. = = 221

To be continued…

Banda Ravipal Reddy,
Director, SIGMA,
Sai Institute of General Mental Ability.