Question

In a train, there were 9x + 12y people. At three successive stations, 3x, 4y and 2x people got down. How many people were left in the train?

Answer ha 4x + 8y​

Answer 1

Answer:

The equations are

3x+4y−k=0

9x+12y−6=0

Here, a

1

=3,b

1

=4,c

1

=−k

and a

2

=9,b

2

=12,c

2

=−6

For the system to have infinite solution if

a

2

a

1

=

b

2

b

1

=

c

2

c

1

⇒

9

3

=

12

4

=

−6

−k

⇒3k=6

⇒k=2