Given that 3 pencils and 4 pens cost K1.04 and 3 pencils and 2 pens cost 64 toea, find:

A. The cost of a pen
B. The cost of a pencil



Answer :

To find the cost of a pen and the cost of a pencil, we can set up a system of linear equations based on the information given. Let's denote:

- The cost of a pencil as [tex]\( a \)[/tex]
- The cost of a pen as [tex]\( b \)[/tex]

We are given two conditions:
1. The cost of 3 pencils and 4 pens is K1.04.
2. The cost of 3 pencils and 2 pens is 64 toea. Note that 64 toea is equal to K0.64 (since 100 toea = 1 kina).

We can set up the following equations based on these conditions:

[tex]\[ 3a + 4b = 1.04 \quad \text{(Equation 1)} \][/tex]

[tex]\[ 3a + 2b = 0.64 \quad \text{(Equation 2)} \][/tex]

To find the values of [tex]\( a \)[/tex] and [tex]\( b \)[/tex], we will solve these two equations simultaneously.

Step-by-Step Solution:

1. Write the system of equations:

[tex]\[ 3a + 4b = 1.04 \][/tex]

[tex]\[ 3a + 2b = 0.64 \][/tex]

2. Subtract Equation 2 from Equation 1 to eliminate [tex]\( a \)[/tex]:

[tex]\[ (3a + 4b) - (3a + 2b) = 1.04 - 0.64 \][/tex]

This simplifies to:

[tex]\[ 2b = 0.40 \][/tex]

3. Solve for [tex]\( b \)[/tex]:

[tex]\[ b = \frac{0.40}{2} \][/tex]

[tex]\[ b = 0.20 \][/tex]

So, the cost of a pen, [tex]\( b \)[/tex], is K0.20.

4. Substitute [tex]\( b \)[/tex] back into Equation 2 to solve for [tex]\( a \)[/tex]:

[tex]\[ 3a + 2(0.20) = 0.64 \][/tex]

[tex]\[ 3a + 0.40 = 0.64 \][/tex]

Subtract 0.40 from both sides:

[tex]\[ 3a = 0.64 - 0.40 \][/tex]

[tex]\[ 3a = 0.24 \][/tex]

5. Solve for [tex]\( a \)[/tex]:

[tex]\[ a = \frac{0.24}{3} \][/tex]

[tex]\[ a = 0.08 \][/tex]

So, the cost of a pencil, [tex]\( a \)[/tex], is K0.08.

Summary:

- The cost of a pencil is K0.08.
- The cost of a pen is K0.20.