Question

The cost of pen equal to the cost of 5 pencils .if 4 pens and 10 pencils cost Rs 90. Find the cost of 5 pens and 6 pencils?

Answer 1

Answer:

Step-by-step explanation:

Here you have it :)

Answer 2

Given that:

• The cost of pen equal to the cost of 5 pencils.
• 4 pens and 10 pencils cost Rs 90.

To Find:

• The cost of 5 pens and 6 pencils.

Let us assume:

• The cost of 1 pen = x
• The cost of 1 pencil = y

According to the question.

ㅤ↠ㅤx = 5y

ㅤ↠ㅤx - 5y = 0 (i)

ㅤ↠ㅤ4x + 10y = 90 (ii)

Adding eqⁿ (i) & eqⁿ (ii).

ㅤ↠ㅤ5x + 5y = 90

ㅤ↠ㅤx + y = 18

ㅤ↠ㅤx = 18 - y

Subtracting eqⁿ (ii) from eqⁿ (i).

ㅤ↠ㅤ-3x - 15y = - 90

ㅤ↠ㅤx + 5y = 30

ㅤ↠ㅤx = 30 - 5y

Now,

ㅤ↠ㅤx = 18 - y (iii)

ㅤ↠ㅤx = 30 - 5y (iv)

Comparing eqⁿ (iii) & eqⁿ (iv).

ㅤ↠ㅤ18 - y = 30 - 5y

ㅤ↠ㅤ- y + 5y = 30 - 18

ㅤ↠ㅤ4y = 12

ㅤ↠ㅤy = 3

Putting the value of y in eqⁿ (iii).

ㅤ↠ㅤx = 18 - 3

ㅤ↠ㅤx = 15

Finding the cost of 5 pens and 6 pencils:

ㅤ∵ㅤThe cost of 1 pen = Rs. 15

ㅤ∴ㅤThe cost of 5 pens = Rs. (15 × 5) = Rs. 75

ㅤ∵ㅤThe cost of 1 pencil = Rs. 3

ㅤ∴ㅤThe cost of 6 pencil = Rs. (3 × 6) = 18

Hence,

• The cost of 5 pens = Rs. 75
• The cost of 6 pencil = Rs. 18