Bissoy.com
Doctors Medicines MCQs Q&A

  1. 38.4 years
  2. 35.5 years
  3. 38 years
  4. 36 years
6 views

1 Answers

Option 1 : 38.4 years

Given:

Total students = 120

The number of boys = 140% of the number of girls

The average age of boys = 24 years

The average age of whole class = 30 years

Calculation:

The ratio of boys and girls = 140 : 100 = 7 : 5

Suppose, the average age of girls is K years.

Sum of the age of whole class = 30 × 12 = 360

According to question -

⇒ (7 × 24) + (5× K) = 360

⇒ 168 + 5K = 360

⇒ 5K = 360 - 168

⇒ K = 192 / 5

⇒ K = 38.4 years

∴ The average age of girls is 38.4 years.

6 views

Related Questions

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)?
1 Answers 9 Views