Question

linear equation in 2 variable

there are 2 class room a and b if 10 students are sent from a and b the no. of students in each room becomes the same if 20 students are sent from b to a the no. of students in a becomes double the no. of students in b find the no. of students in each class room. ​

Answer 1

In the above question, taking number of students in room a = A.

and number of students in room B = B.

if 10 students are sent from a to b, then

A - 10 = B +10 ----> (I)

if 20 students are sent from b to a then,

2 * (B - 20) = A + 20 ----> (II)

2B - 40 = A + 20

A = 2B - 60

replacing A in (I)

A - 10 = B + 10

2B - 60 - 10 = B + 10

B = 80

replacing B = 80

A = (2 * 80) - 60.

A = 100

Answer 2

Let the no. of students in room a= x

let the no. of students in class b = y

according to question,

x -10 = y + 10

equation 1..

(x + 20) =2 ( y -20)

x + 20. = 2y - 40

x. = 2y -60

equation 2....

putting eq 2 in equation 1

x - 10 = y +10

2y - 60 -10 = y + 10

2y - y. = 10 +70

y =80

putting in equation 2

x = 2y - 60

= 2(80) -60

= 160 -60

= 100

no of students in a = 100.

no. of students in b =80