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A student bought 3 notebooks and 1 pen for N35. After misplacing these items, sh...


Question

A student bought 3 notebooks and 1 pen for N35. After misplacing these items, she again bought 2 notebooks and 2 pens, all of the same type for

N30. What is the cost of a pen?

Options

A) N5.00

B) N7.50

C) N10.00

D) N15.00

The correct answer is A.

Explanation:

Represent notebook with x
Represent pen with y
∴ 3x+y=35 ---- (i)
2x+2y=30 ---- (ii)
Multiply eqn (i) by 2 and eqn (ii) by 1
6x+2y=70 ---- (iii)
2x+2y=30 ---- (iv)
Subtract eqn (iv) from eqn (iii)
4x = 40
X = 10
Substitute x = 10 in eqn (i)
3x+y=35
3(10)+y=35
Y = 5
∴ The cost of pen is N5.00

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Dicussion (1)

  • Represent notebook with x
    Represent pen with y
    ∴ 3x+y=35 ---- (i)
    2x+2y=30 ---- (ii)
    Multiply eqn (i) by 2 and eqn (ii) by 1
    6x+2y=70 ---- (iii)
    2x+2y=30 ---- (iv)
    Subtract eqn (iv) from eqn (iii)
    4x = 40
    X = 10
    Substitute x = 10 in eqn (i)
    3x+y=35
    3(10)+y=35
    Y = 5
    ∴ The cost of pen is N5.00

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