Answer:
Ruler: £0.90
Pencil: £0.60
Step-by-step explanation:
Ruler = x
Pencil = y
2x + y = 2.4
5x + y = 5.1
3x = 2.7
x = 0.9
y = 0.6
The cost of a ruler and the cost of a pencil are £0.9 and £0.6 respectively.
Let the ruler be X
Let the pencil be y
Equation 1;
[tex]2x + y = 2.40[/tex]
Equation 2;
[tex]5x + y = 5.10[/tex]
From equation 1, make y the subject of formula
[tex]y = 2.40 - 2x[/tex]
Substitute for y in equation 2,
[tex]5x + y = 5.10[/tex]
[tex]5x + 2.4 - 2x = 5.1[/tex]
[tex]5x - 2x + 2.4 = 5.1[/tex]
[tex]3x + 2.4 = 5.1[/tex]
[tex]3x = 5.1 - 2.4[/tex]
[tex]3x = 2.7[/tex]
[tex]x = \frac{2.7}{3} [/tex]
[tex]x = 0.9[/tex]
Therefore the cost of ruler = £0.9
To find the cost of pencil substitute X into equation 1
[tex]2x + y = 2.4[/tex]
[tex]2(0.9) + y = 2.4[/tex]
[tex]1.8 + y = 2.4[/tex]
[tex]y = 2.4 - 1.8[/tex]
[tex]y = 0.6[/tex]
Therefore, the cost of pencil= £0.6
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