1.

The cost of 4 pencil and 5 pen is Rs 47 and cost of 2 pencil and 7 pen is Rs. 55, then what is the cost of the one pencil?1. Rs. 52. Rs. 33. Rs. 74. Rs. 8

Answer» Correct Answer - Option 2 : Rs. 3

Given:

The cost price of 4 pencils and 5 pens = 47

The cost price of 2 pencils and 7 pens = 55

Calculation:

Let the cost price of pencil be 'x' and pen be 'y'

4x + 5y = 47       ------(1)

2x + 7y = 55      -------(2)

Now, 2 × eq (2) – eq (1)

2(2x + 7y) – (4x + 5y) = 2 × 55 – 47

⇒ 4x + 14y – 4x – 5y = 110 – 47

⇒ 9y = 63

⇒ y = 7

Substituting the value of y in eq (1) then,

⇒ 4x + 5 × 7 = 47

⇒ 4x = 47 – 35

⇒ 4x = 12

⇒ x = 3 

∴ The cost price of one pencil is Rs. 3


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