Question

The total coast of 6book and 7pens is 79rupees and the total coast of 7books and 5pens is 77 rupees find the cost of 1 book and 2pens

Answer 1

6 book and 7 pen = 79 Rs.
7 book and 5 pen = 77 Rs.
1 book and 2 pen = ?

Answer 2

Answer:

cost of 1 book and 2 pens is Rs. 17.15

Step-by-step explanation:

Let the cost of 1 book = x rs

Let the cost of 1 pen =  y  rs.

Now, according to the question,

6x + 7y = 79

and, 7x + 5y = 77

Solving both the equations,

Multiply equation (1) by 5  and (2) by  -7 and adding both equations, we get

30x - 49x + 77y - 77y = 395 - 539

0r, -19 x = -144

⇒ x= 144/19 =  7.57

Cost of 1 book = Rs 7.57

Substituting this in any of the both equation, we get

y =  4.79

Cost of 1 pen = Rs 4.79

So, cost of 1 book and 2 pens = x + 2y = 7.57 + 2(4.79) = Rs. 17.15