The students in three classes are in the ratio 4 : 6 : 9. If 12 students are increased in each class, the ratio changes to 7 : 9 : 12. Then the total number of students in the 2nd Class before the increase is

The students in three classes are in the ratio 4 : 6 : 9. If 12 students are increased in each class, the ratio changes to 7 : 9 : 12. Then the total number of students in the 2^nd Class before the increase is

The Initial ratio is 4 : 6 : 9

Let the common ratio be ‘x’

Therefore the respective number of students in the 3 classes will be 4x , 6x and 9x

After addition of 12 students to each class,

The numbers will be 4x + 12 , 6x + 12, 9x + 12

The ratio after that will be 7 : 9 : 12

∴ (4x + 12)/(6x + 12) = 7/9

∴ 9 × (4x + 12) = 7 × (6x + 12)

∴ 36x + 108 = 42x + 84

∴ 6x = 24

∴ x = 4

∴ The initial number of students in the 2^nd class = 24

the students in three classes are in the ratio 4:6:9. if 12 students are increased in each class, the ratio changes to 7:9:12. then the total number of students in the three classes before the increase is:

24 is the correct answer.

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