## Task 1 - 170621

A scientific expedition covered one-third of the planned total distance on the first day, 150 km on the second day, and one-quarter of the total distance on the third day, thus reaching the destination.

How long was the distance covered by the expedition?
On the first day, $\frac{1}{3}$ and on the third day, $\frac{1}{4}$ of the total distance were covered. Therefore, because $\frac{1}{3}+\frac{1}{4}=\frac{7}{12}$, on these two days $\frac{7}{12}$ of the total distance was covered.

The remaining $150 \mathrm{~km}$ thus correspond to exactly $\frac{5}{12}$ of the total distance. Since $150: 5=30$, it follows that $30 \mathrm{~km}$ is exactly $\frac{1}{12}$ of the total distance; therefore, the total distance is $12 \cdot 30 \mathrm{~km}=360 \mathrm{~km}$.