Question

solve simultaneous equation.
the cost of pen is three times and rs 4 more than the cost of pencil.if tgree pencils and two penscost rs 71 find the cost of each item​

Answer 1

Soln:-

Cost of pen,

x = Rs. 25/-

Cost of pencil,

y = Rs.7/-

Expln:-

cost of pen is denoted as 'x'

cost of pencil is denoted as 'y'

case(1) x = 3y+4

x-3y-4 = 0 ...(1)

case(2) 3y+2x = 71

2x+3y-71 = 0 ...(2)

(2)+(1),

2x+3y-71 = 0

+ x-3y-4 = 0

3x -75 = 0

3x = 75

x = 25 (in equ (1)

3y = x-4

= 21

y = 7

Cost of pen x = Rs. 25/-

Cost of pencil y = Rs.7/-

Answer 2

Answer:

the cost pries of each pen = Rs.25

the cost pries of each pencil = Rs 7

Step-by-step explanation:

Let x and y be the pen and pencil.

According to the question.

x = 3y + 4 ....... (1)

and 2x + 3y = 71 ...... (2)

By substitution equation (1) in (2) get.

2(3y+4) +3y =71

6y +8 + 3y = 71

9y +8 = 71

9y = 71 -8

y = 63\ 9

;. y = 7

the value of put in equation (1) we get,

x = 3x7 + 4

x = 25

i.e the cost pries of each pen(x) = Rs 25

and the cost pries of each pencil(y) = Rs. 7