## Task 2 - 210512

The pioneer groups of classes 5a, 5b, and 5c of a school made book covers for a solidarity bazaar. Class 5a made exactly 6 more covers than class 5b, and class 5c managed to make double what class 5b produced.

In total, the pioneers of the three classes made 66 book covers.

How many book covers did each of the three pioneer groups make?
Assume that class 5a had made 6 fewer covers. Then a total of 60 book covers would have been produced. Furthermore, one could then divide the quantity of these 60 book covers into four equal subsets, such that classes $5 \mathrm{a}$ and $5 \mathrm{~b}$ would have each made one of these subsets, and class 5c would have made the remaining two subsets.

Since $60: 4=15$ and $2 \cdot 15=30$, class 5b has therefore made exactly 15 covers, and class 5c has made exactly 30 covers, while class 5a, due to $15+6=21$, has made exactly 21 book covers.