Home
Class 9
MATHS
The ratio of the number of students in t...

The ratio of the number of students in two classrooms A and B is ` 3 : 2`. If ten students shift form A to B, the ratio becomes ` 7 : 8`. Now how many students must shift from A to B in order for the ratio to become ` 8 : 7`?

A

5

B

10

C

15

D

20

Text Solution

Verified by Experts

The correct Answer is:
A
(i) Let the number of students in the two classes A and B be 2x and 3x respectively.
(ii) Given` (3x - 10) : (2x+10) = 7 : 8`.
Find x from this equation.
(iii) Let y be the number of students to be shifted from A to B.
(iv) Substitute value of x in `(2x - 10 + k) : (3x + 10 - k) = 8 : 7` and find k.
Promotional Banner

Topper's Solved these Questions

  • RATIO, PROPORTION AND VARIATION

    PEARSON IIT JEE FOUNDATION|Exercise Leval 2|20 Videos

  • QUADRATIC EXPRESSIONS AND EQUATIONS

    PEARSON IIT JEE FOUNDATION|Exercise Level 3|23 Videos

  • SALES TAX AND COST OF LIVING INDEX

    PEARSON IIT JEE FOUNDATION|Exercise Level 3|14 Videos

Similar Questions

Explore conceptually related problems

The ratio of the number of students in schools X and Y is 4:7. if 15 students from Y join X, then the ratio becomes 1:1. What is the total number of students in the schools X and Y?

The ratio of the number of students in two classrooms, C_(1) and C_(2) , is 2 : 3 . It is observed that after shifting ten students from C_(1) " to " C_(2) , the ratio is 3 : 7. Further, how many students have to be shifted from C_(2)"to" C_(1) for the new ratio to become 9 : 11 ?

The ratio of the number of students of three class is 2:3:5 .If 20 students are added in each class then the ratio becomes 4:5:7 .Find the number of student in each class before adding .

The ratio of the number of students of three class is 2:3:4 If 12 students are increased in each class then the ratio of becomes 8:11:14 .find the total students of all the three sections before adding 12 students in each class .

The number of students in three classes are in the ratio 2 : 3:5. If 40 students are increased in each class, the ratio changes to 4:5:7. Originally, the total number of students was :

The ratio of Boys and Girls is 5 : 3 . Some students took admission in the ratio 5 : 7. Now total students are 1200 and ratio becomes 7 : 5 . Find the number of students before admission.

There are two class rooms A and B having a certain number of students. If 5 students are shifted from room A to room B, the resulting number of students in both the rooms becomes equal. If 5 students are shifted from room B to room A, the resulting number of students in room A becomes double the number of students left in room B. Find the original number of students in both the rooms separately.

What is the ratio of number of students passed from institute F in 2003 to the number of students passed from institute B in 2005