Question

5 pencil & 7pen together cost 50Rs wheras 7 pencils and 5pen together cost 46rs find the cost of one pencil and that of one pen Answer cost of one pencil 3Rs cost of one pen 5Rs​

Answer 1

Answer:3Rs and 5Rs

Step-by-step explanation:

Let cost of 1 pencil be x Rs and cost of 1 pen be y Rs.

Then,

Cost of 5 pencil be 5x Rs and cost of 7 pens be 7y Rs.

Therefore,

5x+7y= 50 .....eqn 1

Again given that

Cost of 7 pencils and 5 pen together cost 46 Rs.

Therefore,

7x+5y= 46 .....eqn2

On adding both eqn 1 and 2 we got

5x+7y= 50

7x+5y= 46

------------------------------

12x+12y=96

12(x + y)=96

x + y = 8 .....eqn 3

On subtracting eqn 1 and 2 we got

5x+7y =50

7x+5y =46

-----------------------------------

-2x+2y= 4

-2(x - y)=4

x - y = 2 .....eqn 4

On adding eqn 3 and 4 we got

x + y = 8

x - y = 2

----------------------------

x + x = 10

2x = 10

x = 5

Putting value of x in eqn 4 we got

x - y = 2

5 - 2 = y

y = 3

Hence,

Cost of 1 pencil is 5 Rs and cost of 1 pen is 3 Rs.