Let's denote the duration of the shorter call as \( x \) minutes. According to the problem, the longer call lasted 8 minutes longer than the shorter call, which we can express as \( x + 8 \) minutes.
Given that the total duration of the two calls is 42 minutes, we can set up the following equation:
\[ x + (x + 8) = 42 \]
Now, simplify the equation:
\[ 2x + 8 = 42 \]
Next, subtract 8 from both sides:
\[ 2x = 34 \]
Now, divide both sides by 2:
\[ x = 17 \]
So, the shorter call lasted 17 minutes. Now we can find out how long the longer call lasted:
\[ x + 8 = 17 + 8 = 25 \]
Therefore, the shorter call lasted 17 minutes, and the longer call lasted 25 minutes.