How to calculate ground speed using a map with a known scale and time?
If a plane traveled $8\ \mathsf{cm}$ on a map with a scale of $1:1\ \mathsf{million}$, then it traveled $8\ \mathsf{million\ cm}$ in the real-world.

$$8\ \mathsf{million\ cm} = 80,000\ \mathsf{meters} = 80\ \mathsf{km}$$

Convert 80 km in 18 minutes to a speed of kilometers per hour:

$$\frac{80\ \mathsf{km}}{18\ \mathsf{min}} \cdot \frac{60\ \mathsf{min}}{1\ \mathsf{hour}} = 266.6 \frac{\mathsf{km}}{\mathsf{hr}}$$

Groundspeed is traditionally expressed in knots:

$$266.6\ \mathsf{kph} \cdot \frac{0.54\ \mathsf{kts}}{1\ \mathsf{kph}} = 144\ \mathsf{kts}$$

To put this in perspective, 144 kts is a bit fast for a Cessna 172, unless it has a good tailwind, but not at all unreasonable for many small high-performance planes.



The answers to question #44 don't make sense.
The question is "The scale of the chart is...", but the possible answers are all KTS (knots).

The answers to #44 and #45 are clearly reversed.
However, the right answer of 144 kts, is not listed in the possible answers.

In general, I think that test is extremely poor quality.

Question #43 (movement of the earth around the sun) may not even be related to aviation.