The rule implies that the width of the right border is 5px.
What is the width of the right border?
From the question, we have the following CSS rule that can be used in our computation:
div {
border-width: 10px 5px;
}
The border-width property sets the width of an element's border.
If one value is specified, it applies to all four sides of the border.
Since two values are specified, the first value applies to the top and bottom borders, and the second value applies to the left and right borders.
Hence, the width of the right border is 5px.