Question

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.lf 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 row .​

Answer 1

Answer:

100,80

Step-by-step explanation:

Two number of classrooms are 2. They are A and B.

Let the number of students in A be x and number of students in B be y.

(i)

10 students are send from A to B.

⇒ x - 10 = y + 10

⇒ x - y = 20

(ii)

20 students are sent from B to A, the number of students become double.

⇒ x + 20 = 2(y - 20)

⇒ x + 20 = 2y - 40

⇒ x - 2y = -60

On solving (i) & (ii), we get

⇒ x - y = 20

⇒ x - 2y = -60

   -----------------------

        y = 80

Substitute y = 80 in (i), we get

⇒ x - y = 20

⇒ x - 80 = 20

⇒ x = 100.

Therefore:

Number of students in classroom A = 100.

Number of students in classroom B = 80.

Hope it helps!

Answer 2

Let a and b be the number of students in halls A and B respectively, such that a > b.

Then, if 10 students are transferred from a to b, the number of students are equal.

Therefore, a-10 = b+10

or a - b = 20 ---------- (1)

Similarly, if 20 students are sent from hall B to hall A, then the number of students in Hall A would be twice that of the students in Hall B.

Then, a+20 = 2(b-20)

or a + 20 = 2b - 40

or 2b - a = 60 ------- (2)

Adding equations (1) and (2), we get

2b - a = 60

a - b = 20

Therefore, on adding we get, b = 80

Substituting the value of b = 80 in equation 1, we get

a - 80 = 20

or a = 100.

Therefore there are 100 students in Hall A and 80 students in Hall B