Question

4) The students are in the ratio 2:3:5.if 20 students are increased in each batch the ratio changes to 4:5:7.The total number of students in the three batches before the increase was?

Answer 1

Ratio of students = 2:3:5
Let the number of students be 2x, 3x and 5x respectively in three batches.

If 20 students are increased,
(i)The students in the three batches became (2x+20), (3x+20) and (5x+20).
(ii)The ratio changes to 4:5:7.
So, the number of students became 4x, 5x and 7x respectively in three batches.

According to question, the equation formed is (2x+20) + (3x+20) + (5x+20) = 4x + 5x + 7x
On solving the equation, we will get x as 10.

Hence, number of students in the three batches before the increase were 20, 30 and 50.

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Answer 2

Answer:

Step-by-step explanation:

We wants to find number of students.

As per the question, 2:3:5 = 4:5:7

We need to take x is number of students

We Need to multiply by x with the ratio.

now, 2x:3x:5x = 4x:5x:7x

Number of students increases = 20

Number of students = x

Now, evaluate any 2 ratios with increased Students.

5x + 20 = 7x

5x - 7x = -20

-2x = -20

x= 10 .

So, Before increases, the number of students is 10.