Question

The price of 3 doors and 5 windows is Rs. 487
and the price of 5 doors and 3 windows is
Rs. 561. Find the price of 1 door.
(A) Rs. 47
(B) Rs. 56
(C) Rs. 76
(D) Rs. 84​

Answer 1

if we solve it by method of elimination answer will be 83.8125 which is aprrox.84

Step-by-step explanation:

suppose door is x

and window is y

3 doors + 5 windows = rs.487

5 doors + 3 windows = rs.561

equations will be

3x + 5y = 487-----(1)

5x + 3y = 561-----(2)

multiplying equation (1) by 3 and (2) by 5

we will get new equations as...

9x + 15y = 1461----(1A)

25x + 15y = 2805----(2A)

Elimination of equations (1A) and (2A)

25x + 15y = 2805

9x + 15y = 1461

- - -

_______________

16x = 1341

x = 1341/16

x = 83.8125

x = 84(approx.)

cost of 1 door is rs.84