2407. The shooter makes 3 shots. The probabilities of hitting in the first, second and third shots are respectively 0.7; 0.8; 0.9. Find the probability that as a result of these shots will
a) not a single hit;
b) at least one hit;
c) exactly one hit;
d) exactly three hits.

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)