3. When asked how many sheep were in the flock, the shepherd replied: "60 sheep are drinking water, and the rest, 0.6 of all the sheep, are grazing." How many sheep are in the flock?
3. 60 sheep constitute 0.4 of all the sheep $(1-0.6=0.4)$. Therefore, the total number of sheep in the flock is $60: 0.4=150$.