Question

3 notebooks and 10 pencil cost 300 2 notebooks and pencil cost rs 145 find the cost of 4 notebooks and 3 pencil​

Answer 1

pencil cost-155

notebook cost-304

Answer 2

Given:

3 notebooks and 10 pencil cost rs. 300

2 notebooks and pencil cost rs 145

To find:

The cost of 4 notebooks and 3 pencil​

Solution:

Let's assume,

"n" → represents the cost of a notebook

"p" → represents the cost of a pencil

So, according to the question, we can form two equations as follows:

Equation 1: → 3n + 10p = 300

and

Equation 2: → 2n + p = 145

On multiplying equation 2 by 10 throughout, we get

20n + 10p = 1450 ...... [Equation (3)]

By subtracting equation (2) from (3), we get

20n + 10p = 1450

3n + 10 p = 300

-     -           -

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17n = 1150

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∴ n = $\frac{1150}{17} = \bold{67.64}$ ← cost of a notebook

Substituting the value of n in eq. (2), we get

$(2\times 67.64) + p = 145$

$\implies 135.28 + p = 145$

$\implies p = 145 - 135.28$

$\implies \bold{p = 9.72}$ ← cost of a pencil

∴ 4n + 3p = (4 × 67.64) + (3 × 9.72) = 270.56 + 29.16 = 299.72 ≈ 300

Thus, the cost of 4 notebooks and 3 pencils is → Rs. 300 approximately.

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