The problem is to solve the inequality $3u < 15$ and graph the solution on a number line.

1. Problem Description

The problem is to solve the inequality $3u < 15$ and graph the solution on a number line.

2. Solution Steps

First, we need to solve for $u$ in the inequality $3u < 15$.

To isolate $u$, we divide both sides of the inequality by 3:

$\frac{3u}{3} < \frac{15}{3}$

$u < 5$

The solution to the inequality is $u < 5$.

To graph this on a number line, we need an open circle at 5, since the inequality is strictly less than (not less than or equal to). The arrow will point to the left, indicating that all values less than 5 are solutions.

3. Final Answer

The solution to the inequality is $u < 5$. On the number line, we place an open circle at 5 and draw an arrow pointing to the left.