Question

the cost of 6 tables and 5 chairs is rs 790 find the cost of 11 tables and 7 chairs if the cost of 5 tables is same as the cost of 9 chairs​

Answer 1

Answer:

Solution

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Let us consider,

Cost of one chair =Rs x and

Cost of one table =Rs y

As per the statement,

5x+4y=Rs 5600...(1)

4x+3y=Rs 4340....(2)

Using elimination method:

Multiply (1) by (3) and (2) by 4. And subtract both the equations.

15x+12y=16800

16x+12y=17360

− − −

_________________

−x =−560

So, x=560

From (1)

5×560+4y=5600

2800+4y=5600

4y=5600−2800

4y=2800

y=700

Answer

Cost of one chair =Rs 560

and cost of one table =Rs 700

Answer 2

Let us consider,

Cost of one table =Rs x and

Cost of one chair =Rs y

As per the statement,

6x+5y=Rs 790...(1)

5x = 9y

x = 9y/5....(2)

by putting eq2 in eq1

6(9y/5)+5y = 790

54y+25y = 3950

79y = 3950

y = 50

put the value of y in eq1

so, 6x+5(50) = 790

6x = 540

x = 90

so the value of 11x+7y

11(90)+7(50)

990+350

=>. Rs 1340. ans.