Question

Can any 1 plz help me do this sum

Answer 1

Answer:

Step-by-step explanation:

Let the cost of one pencil be x

The cost of one pen be y

According to the first condition

5x + 7y =50

According to the second condition

7x + 5y = 46

Here first add the equation

Then substract the equation

2new eq will be there subtract and substitute

U will get the answer

Answer 2

let cost of one pencil= rs. x

and cost of one pen= rs. y

ATQ..

5x + 7y = 50......(1)

7x + 5y = 46......(2)

Now from eq.(1)..

x=

$\frac{50 - 7y}{5}$

put in eq (2)

$7( \frac{50 - 7y}{5}) + 5y = 46 \\ \frac{350 - 49y + 25y}{5} = 46 \\ 350 - 24y =23 0 \\ 24y = 350 - 230 \\ 24y = 120 \\ y = 5$

Put value of y in eq (1)..

$x = \frac{50 - 7 \times 5}{5} \\ x = \frac{50 - 35}{5} \\ x = \frac{15}{5} \\ x = 3$

So, cost of one pencil= rs. 3

and cost of one pen= rs.5

thanks.

hope it helps you