Question
In a school, the average number of books that some
numbers of boys have is 80 and average number of books that some numbers of girls have is 50. If each boy have read 5 books then the average numbers of unread books with all the students become 70. The total number of boys is what percentage of the total number of students in that school?Solution
Let the total number of boys be x. and the total number of girls be y. The total number of books boys have = 80x The total number of books the girls have = 50y If each of the boy have read 5 books, then the remaining number of unread books = 80x – 5x = 75x The sum of the all the books = 70(x + y) = 75x + 50y 20y = 5x x : y = 4 : 1 Required % = (4/5) × 100 = 80%
The average of five consecutive odd numbers is 61. What is the average of the first three numbers among them?
A student's marks were wrongly entered as 65 instead of 45. Due to this, the average marks for the class increased by 1 /3 The number of students in the...
The number of students in class 'A' is 104, and the ratio of girls to boys is 4:9. If the average number of boys in classes 'A' and 'B' is 124, and the ...
The average number of Scholarship received by (5p + 2) students is ‘p’. If there had been 8 students less then each student would have got (p + 2) S...
Average number of pages in 54 books is 240. Two more books with pages (b + 20) and (b - 8) are added, and the average becomes 242. Find (b - 100).
A number is such that when it is multiplied by 4, it gives another number which is as much above from 180 as the original number (itself) is below 180. ...
- There are 45 players in a sports camp with an average age of 26 years. 5 more players join, decreasing the average to 25. Find the average age of the new p...
The average of 10 observations is 46. It was realized later that an observation was misread as 42 in place of 142. The correct average is:
Average of 8 numbers is 50. If average of first four and last two numbers is 60 and 70, respectively then find the fifth number given that ratio of fift...
A student's average score across five subjects is 80. If the scores in four subjects are 78, 85, 82, and 88, what is the average of the top three highes...
