A shopkeeper bought 5 dozen pens at 85 cents per pen and planned to sell each for 1 Birr. However, [tex]$10\%$[/tex] of the pens were damaged and thrown away. How much did he profit?



Answer :

Certainly! Let's break down the problem step-by-step to determine the profit made by the shopkeeper.

1. Number of Pens Bought:
- The shopkeeper bought 5 dozen pens.
- Since 1 dozen is equal to 12 pens, the total number of pens bought is:
[tex]\[ 5 \text{ dozen} \times 12 \text{ pens/dozen} = 60 \text{ pens} \][/tex]

2. Cost per Pen:
- Each pen was bought at a cost of 85 cents. Converting this to Birr (since 1 Birr = 100 cents):
[tex]\[ 85 \text{ cents} = 0.85 \text{ Birr} \][/tex]

3. Total Cost:
- The total cost of the pens can be calculated by multiplying the number of pens by the cost per pen:
[tex]\[ 60 \text{ pens} \times 0.85 \text{ Birr/pen} = 51 \text{ Birr} \][/tex]

4. Damage Rate:
- 10% of the pens were damaged and had to be thrown away. Let's determine the number of damaged pens:
[tex]\[ 0.10 \times 60 \text{ pens} = 6 \text{ pens} \][/tex]

5. Undamaged Pens:
- The number of undamaged pens is the total number of pens minus the number of damaged pens:
[tex]\[ 60 \text{ pens} - 6 \text{ pens} = 54 \text{ pens} \][/tex]

6. Selling Price per Pen:
- Each undamaged pen was sold for 1 Birr.

7. Total Revenue:
- The total revenue generated from selling the undamaged pens can be calculated by multiplying the number of undamaged pens by the selling price per pen:
[tex]\[ 54 \text{ pens} \times 1 \text{ Birr/pen} = 54 \text{ Birr} \][/tex]

8. Profit:
- Finally, profit is the total revenue minus the total cost:
[tex]\[ \text{Profit} = 54 \text{ Birr} - 51 \text{ Birr} = 3 \text{ Birr} \][/tex]

So, the shopkeeper made a profit of 3 Birr.