Question

5 pencils and 7 pens together quotes cost Rupees 50 whereas 7 pencils and 5 pens together cost rupees for 4


6 find the cost of one pencil and that of one pen

Answer 1

Answer:-

Pen cost is Rs 5.

Pencils cost Rs 3

Q. 5 pencils and 7 pens together quotes cost Rupees 50 whereas 7 pencils and 5 pens together cost rupees for 46 find the cost of one pencil and that of one pen.

Solution :-

Let the cost of pencils be x and cost of pens be y.

5 pencil and 7 pens cost = Rs 50

also, $5x + 7y = 50$----eq.2

7 pencils and 5 pens cost = Rs 46

also, $7x + 5y = 46$---eq.2

Now add eq. 1 and 2.

$5x + 7x +5y +7y = 50+46$

$12 x + 12 y = 96$

$x + y = 8$---3

Now,subtract eq.1 and 2.

$\implies$ $5x - 7x +7y -5y = 50 -46$

$\implies$ $-2x +2y = -4$

$\implies$ $-x +y = 2$-----4

Now add eq 3 and 4

$\implies$ $x -x +y+y = 10$

$\implies$ $2y = 10$

$\implies$ $y = 5$

Pen cost is Rs 5.

Pen cost is Rs 5.Pencils cost Rs 3

Answer 2

Answer:

X=4.12,y=4

Step-by-step explanation:

take a pencil as X. and.a pen as y now equate 5x+7y=50,7x+5y=46 by multiplying 1st equation with 7and 2nd. equation. with 5.then u get approximately y=4.3then sub substitute y in equation. 1r2 u will get X=4.12