Question

solve Q 8 of this attachment fast ​

Answer 1

Step-by-step explanation:

Let the cost of one pencil be'a®'

Let the cost of one pen be 'b®'

A/C (1)= 6a+5b=9---(equation 1)

A/C (2)=2a+3b=5---(equation 2)×3

=6a+9b=15--(equation 3)

Subtracting equation 1 from equation 3

6a-6a+9b-5b=15-9

4b=6

b=(3/2) or 1.5®

Putting b=(3/2) in equation 2

2a+3(3/2)=5

2a+(9/2)=5

(4a+9)/2=5

4a+9=10

a=(1/4) or 0.25®

Answer 2

Answer:-

Let the cost of a pen be "x" and the cost of a pencil be "y".

Given:

Cost of 5 pens and 6 pencils = Rs. 9

→ 5*x + 6*y = 9

→ 5x + 6y = 9 -- equation (1)

And,

Cost of 3 pens and 2 pencils = Rs. 5

→ 3*x + 2*y = 5

→ 3x + 2y = 5 -- equation (2).

Multiply equation (2) by 3 and subtract equation (1) from (2).

→ 3 (3x + 2y) - (5x + 6y) = 3(5) - 9

→ 9x + 6y - 5x - 6y = 15 - 9

→ 4x = 6

→ x = Rs. 6/4

Substitute the value of x in equation (1).

→ 5(6/4) + 6y = 9

→ 6y = 9 - 30/4

→ 6y = (36 - 30) / 4

→ y = 6/4 * 1/6

→ y = Rs. 1/4

Hence,

• Cost of a pen = 6/4 * 100 P = 150 P

• Cost of a pencil = 1/4 * 100 P = 25 P

Verification:

Cost of 5 pens and 6 pencils = Rs. 9

→ 5 * 150 + 6 * 25 = 9 * 100

→ 750 + 150 = 900

→ 900 P = 900 P

And,

Cost of 3 pens and 2 pencils = Rs. 5

→ 3 * 150 + 2 * 25 = 5 * 100

→ 450 + 50 = 500

→ 500 P = 500 P

Hence, Verified.