alleryWhat is the arithmetic mean of 12, 15, 18, 21 and 24?
- 16
- 17
- 19
- 18
Show answer and solution
Correct answer: D. 18
The five values add up to 90, and 90 divided by 5 gives 18.
SSC CGL Arithmetic Mean — practice questions
Explore 51 free Arithmetic Mean questions in SSC CGL Quantitative Aptitude. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–30 of 51.
What is the arithmetic mean of 12, 15, 18, 21 and 24?Read the answer and worked solution →The mean of five numbers is 21. Four of them are 12, 18, 25 and 30. What is the fifth?Read the answer and worked solution →The mean of 8 numbers is 25. If every number is increased by 6, the new mean isRead the answer and worked solution →The mean of 40 students' marks is 65 and of another 60 students is 70. What is the mean of all 100?Read the answer and worked solution →Six members of a family average 30 years. A member aged 45 leaves. The new average age isRead the answer and worked solution →The mean of 30 observations is 40. One value 63 was read as 36. The correct mean isRead the answer and worked solution →A batter averages 32 after 9 innings. A score of 72 in the 10th innings makes the averageRead the answer and worked solution →A shopkeeper mixes 4 kg rice at Rs 40 per kg with 6 kg at Rs 50 per kg. The mean price per kg isRead the answer and worked solution →What is the median of 7, 3, 9, 5 and 11?Read the answer and worked solution →Find the median of 9, 14, 6, 11, 20, 3 and 17.Read the answer and worked solution →The data 2, 3, 3, 5, 5, 8 has which mode?Read the answer and worked solution →A set has mean 20 and median 17. By the empirical relation, its mode isRead the answer and worked solution →The values 2, 4, 4, 4, 5, 5, 7, 9 have a population standard deviation ofRead the answer and worked solution →What is the standard deviation of the values 6, 6, 6 and 6?Read the answer and worked solution →If 5 is added to every value in a data set, its standard deviationRead the answer and worked solution →A data set has standard deviation 3. Each value is multiplied by 4. The new standard deviation isRead the answer and worked solution →If the variance of a data set is 49, its standard deviation isRead the answer and worked solution →A data set has standard deviation 6. Its variance isRead the answer and worked solution →What is the range of the values 14, 9, 31, 22 and 5?Read the answer and worked solution →The sum of the deviations of all observations from their arithmetic mean is alwaysRead the answer and worked solution →The mean of five consecutive integers is 12. The largest of them isRead the answer and worked solution →Five consecutive even numbers have an average of 30. The smallest isRead the answer and worked solution →The average of three numbers is 14. Two of them are 10 and 16. The third isRead the answer and worked solution →Seven numbers average 18. The first four average 16 and the last four average 20. The fourth isRead the answer and worked solution →Class A has 20 pupils averaging 52 and class B has 30 pupils averaging 62. The combined average isRead the answer and worked solution →Five numbers average 27. After one is removed, the other four average 25. The removed number isRead the answer and worked solution →The value 10 occurs 3 times, 20 occurs 5 times and 30 occurs 2 times. The mean value isRead the answer and worked solution →The values 1, 2, 3 and 4 occur 5, 9, 12 and 7 times. The modal value isRead the answer and worked solution →Six numbers average 15. A seventh number is added and the average becomes 16. The seventh isRead the answer and worked solution →If every observation is divided by 5 and the old mean was 45, the new mean isRead the answer and worked solution →
Worked practice questions
The mean of five numbers is 21. Four of them are 12, 18, 25 and 30. What is the fifth?
- 18
- 19
- 22
- 20
Show answer and solution
Correct answer: D. 20
Total is 5 x 21 = 105, and the four known numbers sum to 85, leaving 20.
The mean of 8 numbers is 25. If every number is increased by 6, the new mean is
- 27
- 29
- 33
- 31
Show answer and solution
Correct answer: D. 31
Adding a constant to every value shifts the mean by that same constant, giving 31.
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