A student bought 3 notebooks and 1 pen for N35 ... - WAEC Mathematics 2003 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?
N30. What is the cost of a pen?
A
N5.00
B
N7.50
C
N10.00
D
N15.00
correct option: a
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
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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