Question

2 pencils and 3 pens cost Rs. 8. 3 pencils and 2 pens cost Rs. 7. What is the cost of 5 pencils and 5 pens? (in Rs. )

Answer 1

Answer:

15₹

Explanation:

Let cost of 1 pen be x

let cost of 1 pencil be y

(2y+3x=8)*3-----------Given----eq1

(2x+3y=7)*2--------------Given----eq2

sub eq 1 and 2

6y+9x=24

6y+4x=14

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

0+5x=10

x=10|5

x=2

sub x in eq 1

6y+2(18)=24

6y=24-18

6y=6

y=1

cost of 1 pen=2₹

cost of 1 pencil =1 ₹

cost of 5 pens and 5 pencils

5*2+5*1=cost

cost=10+5

cost=15₹

Answer 2

Answer:

cost of 5 pencil and pen is Rs 15

Step-by-step explanation:

let the cost of one pencil = x

and the cost of one pen = y

2x + 3y = 8 ------------(1)

3x + 2y = 7 -------------(2)

on multiply 3 in eq 1 and 2 in eq 2

3(2x + 3y = 8)

6x + 9y = 24 -------(3)

2(3x + 2y = 7)

6x + 4y = 14 ---------(4)

on subtract eq 3 and 4

6x + 9y = 24

6x + 4y = 14

- - -

5y = 10

y =10/5

y = 2

put y in eq 1

2x + 3y = 8

2x + 3(2) = 8

2x + 6 = 8

2x = 8 - 6

2x = 2

x = 2/2

x = 1

cost of 1 pencil = 1

cost of 5 pencil = 5 × 1 = Rs 5

cost of 1 pen = 2

cost of 5 pen = 2 × 5 = Rs 10

cost if 5 pencil and 5 pen = 5 + 10 = 15