Question

3 chairs and 2 tables cost Rs 700, while 5 chairs and 3 tables cost Rs 1100. what is the cost of 2 chairs and 2 tables?

Answer 1

let chair=x and table=y

3x+2y=700...(1)
9x+6y=2100


5x+3y=1100...(2)

10x+6y=2200
9x+6y=2100

so we get x=100
y=700-400/2=200

2x+2y=2(100)+2(200)=200+400=600

Answer 2

let the cost of chairs be x
let the cost of tables be y
3x + 2y = 700 (Multiply by 5)
5x + 3y = 1100 (Multiply by 3)

15x + 10y = 3500
15x + 9y = 3300
subtract
y= 200
Substitute the value in equation

3x + 400 = 700
3x = 300
x = 100

Cost of 2 tables and 2 chairs= 2 x 100 + 2 x 200= 600