Based on age, a class of students is divided into three groups, A, B and C, such that the sum of the ages of the students in the three groups is in the ratio 19 ∶ 21 ∶ 20. If a teacher of age 58 years is added to group A and another teacher of 22 years is added to group B, then a teacher of what age should be added to group C, so that the ratio of the sum of ages of the three groups become 1 ∶ 1 ∶ 1?

Based on age, a class of students is divided into three groups, A, B and C, such that the sum of the ages of the students in the three groups is in the ratio 19 ∶ 21 ∶ 20. If a teacher of age 58 years is added to group A and another teacher of 22 years is added to group B, then a teacher of what age should be added to group C, so that the ratio of the sum of ages of the three groups become 1 ∶ 1 ∶ 1? Correct Answer 40 years

Let the sum of the ages of students in groups A, B and C be ‘19x’ years, ‘21x’ years and ‘20x’ years respectively.

After adding teachers to groups A and B,

⇒ Sum of ages of group A = (19x + 58)

⇒ Sum of ages of group B = (21x + 22)

Final ratio of sum of ages of groups A and B = 1 ∶ 1

⇒ (19x + 58) = (21x + 22)

⇒ 2x = 36

⇒ x = 36/2 = 18

Now, let the age of teacher to be added in group C be ‘y’ years.

Sum of ages of group C = (20x + y) years

Also, final ratio of sum of ratio of groups B and C = 1 ∶ 1

⇒ (21x + 22) = (20x + y)

⇒ y = x + 22

Substituting for x,

⇒ y = 18 + 22 = 40 years

∴ A teacher of 40 years should be added to group C

Related Questions

Each question below is followed by two statements I and II. You have to determine whether the data given in the statements are sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer. What is the average weight of new students added? I. In a class 60% students are male and there average weight is 15 kg more than the female students, 9 males and 6 new female students joined the class and the average weight of the class increased by 0.84 II. Total male students in the class is 12 more than female students adding 9 male students to the class increases the average weight of male students by 1 kg and adding 6 female students increases the average weight of female students by 0.6.