To solve the problem, we have the following:
a. Calculate the amount of the article increase.
The amount of increase can be calculated as follows:
\[ \text{Increase} = \text{Selling Price} - \text{Cost Price} \]
Where:
- Selling Price = N$200
- Cost Price = N$125
\[ \text{Increase} = 200 - 125 = N$75 \]
So, the amount of the article increase is N$75.
b. Calculate the percentage increase.
The percentage increase can be calculated using the following formula:
\[ \text{Percentage Increase} = \left(\frac{\text{Increase}}{\text{Cost Price}}\right) \times 100 \]
Using the increase calculated in part (a):
\[ \text{Percentage Increase} = \left(\frac{75}{125}\right) \times 100 \]
Calculating that:
\[ \text{Percentage Increase} = 0.6 \times 100 = 60% \]
So, the percentage increase is 60%.