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:  Choose the correct choice.
A) Rs. 3500
B) Rs. 3600
C) Rs. 3900
D) Rs. 4000
E) Rs. 4100
Let the cost of a chair and that of a table be Rs. x and Rs. y respectively.   Then, 10x = 4y or y = 5 x.   2   15x + 2y = 4000   15x + 2 x 5 x = 4000   2   20x = 4000   x = 200.   So, y = 5 x 200 = 500.   2   Hence, the cost of 12 chairs and 3 tables = 12x + 3y   = Rs. (2400 + 1500)   = Rs. 3900.   Rs. 3900
<result>C</result>
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: