Bissoy.com
Doctors Medicines MCQs Q&A

The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of all the boys in the class becomes:

The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of all the boys in the class becomes: Correct Answer 11 years

According to the question,
Average
= $$\frac{20 × 12 + 5 × 7}{25}$$
= $$\frac{240 + 35}{25}$$
= $$\frac{275}{25}$$
= 11 years

Related Questions

Questions below followed by three quantities. Find the relationship between them. Quantity I: Average age of 14 members of team is 25 years. While oldest member of the team is 26 years older than youngest member of the team. Out of remaining 12 members of team, average age of six members of team is 28 years and the remaining six members is 20 years. What is the age of oldest member of the team? Quantity II: Average age of Nitu, Rekha and Shyam is 17 years. Two new persons Divya and Raju joined them so that average age of all become 19 years. If Divya is 2 years older than Raju and Rekha is 2 years older and 1 year older than Shyam and Nitu respectively. What is sum of the average age of Nitu and Shyam together and average age of Divya and Rekha together? Quantity III: The average age of father, mother and their two sons is 27.5. Five years ago, the ratio of ages of father, mother and two sons (elder and younger) is 7 : 5 : 2 : 1. Find the sum of ages of two sons after 7 years.
Quantity I: The average age of a cricket team of 11 players is x years. After three years, four players leave the team and four new players join in place of them then the current average age becomes (x + 2) years. The current average age of the players who left the team was 18 years then find the average of the current age of the 4 new joiners? Quantity II: In a group of 6 students, the average age of the 5 youngest students is 12 years and the average age of the 5 oldest students is 15 years. What is the average age of all the students? (it is given that the age of them is in arithmetic progression)?
In a company there are 252 engineers, in which the ratio of the number of electronics engineers and computer engineers is 2 ∶ 1. The ratio of the number of electronics engineers and computer engineers becomes 1 ∶ 1 after recruitment of some more computer engineers. The average age of all the engineers is now 22 years and the average age of the computer engineers is 2 years less than the average age of electronics engineers. (A) The average age (in years) of electronics engineers is 21 (B) The average age (in years) of computer engineers is 21 (C) The average age (in years) of electronics engineers is 23 (D) The average age (in years) of electronics engineers is 25 (E) The average age (in years) of computer engineers is 23 Choose the correct answer from the options given below: 
The average age of 30 boys in a class in 15 years. One boy, aged 20 years, left the class, but two new boys came in his place whose age differs by 5 years. If the average age of all the boys now in the class becomes 15 years, the age of the younger newcomer is :
Given below are quantities named A,B and C. Based on the given information, you have to determine the relation between the quantities. You should use the given data and your knowledge of mathematics to choose among the possible answer. Akash’s present age is six years less than Badshah’s age after nine years. The ratio of present age of Badshahand RAFTAAR is 5:9. Raftaar is 21 years younger than Denny and Denny is three years older than Honey. Square of the Honey’s present age is 1350 more than 15 times of Honey’s present age? Quantity A: What is the difference between AKASH’s present age and HONEY’s age after 16 years? Quantity B: After 6 years Mankirat’s age is twice that of Akash’s present age. Diljeet’s present age is 3.5 times of 25% of sum of present age of Mankirat and A. What is the present age of Diljeet? Quantity C: Twice of A’s present age is eight years more than that of Babbu’spresent age, then find the Babbu’s present age?
The average age of 5 boys of a class is 15. If 7 more boys are admitted to the class with average age 12, and 3 of the existent boys leave the class with the average age 13, what will be the new average age of the boys of the class?
A class has 20 boys and 20 girls. The average age of girls in the class is 16 years and the average age of boys in the class is 17 years. One girl and one boy leave the class and the average age of the girls reduced by 1 year and that of boys reduced by 2 years. Find the new average age of the whole class.
The average age of 80 boys in a class is 15 years. The average age of a group of 15 boys in the class is 16 years and the average age of another 25 boys in the class is 14 years. What is the average age of the remaining boys in the class?
Questions below followed by three quantities. Find the relationship between them. Quantity I: In a class with a certain number of students if a teacher weighing 78 kg is added, then average weight of class is increased by 2 kg. If one more teacher weighing 66 kg is added, then the average weight of the class increases by 3.5 kg over the original average. What is the original average weight (in kg) of the class? Quantity II: The average age of 16 students and their teacher's age is 16 years. If the teacher's age is excluded, the average reduces by 2. What is the teacher's age? Quantity III: Average weight of three friends A, B and C is 46 kg. Another person D joins the group and now the average is 45 kg. If another person E whose weight is 6 kg more than D, joins the group replacing A, then average weight of B, C, D and E becomes 47 kg. What is the weight of A (in kg)?
The average of the ages of 15 students in a class is 19 years. When 5 new students are admitted to the class, the average age of the class becomes 18.5 years. What is the average age of the 5 newly admitted students?