The average of 11 results is 50, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
Correct answer: B. 56
- A. 46
- B. 56
- C. 34
- D. 57
Explanation
The total of 11 results is 11 x 50 = 550, while the first six total 6 x 49 = 294 and the last six total 6 x 52 = 312. The first-six and last-six groups overlap in the sixth result, so the sixth result is 294 + 312 - 550 = 56. The likely mistake is choosing 46 by subtracting the two group totals in the wrong way.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Averages
An average represents the total of a set of values divided by the number of values, and a weighted average gives different importance to different groups. Problems involve missing values, combined averages, replacement of observations, and changes in the average, so the total and count must be tracked separately.
Practise Arithmetic
1,060 free Arithmetic MCQs from Mathematics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Mathematics questions like this
Mathematics is on 76 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Averages questions
Find the average of the first 20 natural numbers?
A batsman makes a score of 64 runs in the 16th innings and thus increased his average by 3. Find his average after the 16th inning?
The average marks of a class of 30 students is 40 and that of another class of 50 students is 60. Find the average marks of all the students?
The average of five results is 46 and that of the first four is 45. The fifth result is__________?
Three years ago the average age of a family of six members was 19 years. A boy have been born, the average age of the family is the same today. What is the age of the boy?
The average weight of 25 persons sitting in a boat had some value. A new person added to them whose weight was 46 kg only. Due to his arrival, the average weight of all the persons decreased by 5 kg. Find the average weight of first 25 persons?