Question

The cost of 4 pens and 4 pencil boxes is Rs.100. Three times the cost of a pen is Rs.15 more than the cost of a pencil box. Form the pair of linear equations for the above situation. Find the cost of a pen and a pencil box

Answer 1

Let the cost of the pen be Rs x and the cost of pencil pox be Rs y

Given that the cost and 4 pencil boxes and 4 pens = Rs 100
⇒ 4x + 4y = 100
Taking 4 as common
⇒ x + y = 25 (Equation 1)

Also given that 3 times the cost of the pen is 15 more than the pencil box
⇒ 3x = y + 15
⇒ 3x - y = 15 (Equation 2)

Adding equation 1 and equation 2
x + y = 25
3x - y = 15

4x = 40
x = 10

3(10) - y = 15
30 - 15 = y
y = 15

The cost of the pen is Rs 10 and the cost of the pencil box = Rs 15


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Answer 2

Answer:

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