Question

The price of 10 chairs is equal to that of 4 tables. The price of 15 chairs and 2 tables together is Rs. 4000. The total price of 12 chairs and 3 tables is:

Answer 1

Let the price of one chair be x, and price of one table be y

From the question:

10x = 4y ........................................(1)

15x + 2y = 4000 ............................(2)

now, if we divide ....(1) by 2

5x=2y   ... substitute value of 2y in ....(2)

15x+5x=4000
20x=4000
x=200

in.... (1) substitute x=200

2000=4y
y= 500

Now we the required form,

12x + 3y = (12×200)+(3×500)
              =2400+1500
              =3900 Rs

Answer 2

Let the price of a chair = Rs x

and the price of a table = Rs y

According to question :

The price of 10 chairs is equal to that of 4 tables

10 x = 4 y

5x = 2y

And

The price of 15 chairs and 2 tables together is Rs. 4000

15x + 2y = 4000

putting value of 2y = 5x

15x + 5x = 4000

20x = 4000

x = Rs.200

y = 5/2 (200) = Rs.500

Thus , price of a chair is Rs.200 and that of a table is Rs.500 .

Hence price of 12 chairs and 3 tables is

= Rs.12(200) + Rs.3(500)

= Rs.2400 + Rs.1500

= Rs.3900

Therefore, the total price of 12 chairs and 3 tables is Rs.3900