Question

The price of 3 notebooks and 8 pens is 100 rupees the price of 2 notebooks and 5 pens is 65 rupees what is the price of a notebook? what is the price of pen?
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Answer 1

Answer:

The cost of book is 20rs each &the cost of pen is 5rs each

Step-by-step explanation:

1] 3x+8y=100

2] 2x+5y=65

multiply 2 for equation 1 & 3 for equation 2

2(3x+8y)=2(100)

3(2x+5y)=3(65)

which forms

6x+16y=200-1️⃣

6x+15y=195-2️⃣

substrate the above equations

1y=5

substitute 5in the place of y

3x+8y=100

3x+8(5)=100

3x+40=100

3x=100-40

3x=60

x=60/3

x=20

Answer 2

Given:

Let the price of notebooks = x

Let the price of pens = y

3x+8y=100    -(1)

2x+5y=65       -(2)

multiply equation (1) by 2 and equation (2) by 3

Here

6x+16y=200

6x+15y=195

y=5

Put value of y in equation (1)

3x+8*5=100

3x+40=100

3x=100-40

3x=60

x=60/3

x=20

Hence Notebooks price is 20 and pens price is 5