There are two classrooms A and B. If 10 students are sent from A to B, the number of students in each room becomes the same. If 20 students are sent from B to A, the number of students in A becomes double the number of students in B. Find the number of students in each room.

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1 Answers

Let the number of students in classroom A be x 

Let the number of students in classroom B be y. 

If 10 students are transferred from A to B, then we have: 

x – 10 = y + 10 

⇒x – y = 20 …..(i) 

If 20 students are transferred from B to A, then we have: 

2(y – 20) = x + 20 

⇒2y – 40 = x + 20 

⇒ -x + 2y = 60 …..(ii)

On adding (i) and (ii), we get: 

y = (20 + 60) = 80 

On substituting y = 80 in (i), we get: 

x – 80 = 20 

⇒x = (20 + 80) = 100 

Hence, the number of students in classroom A is 100 and the number of students in classroom B is 80. 

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