3607. Among the parts arriving at the assembly from the first machine, 0.1% is defective, from the second - 0.2%, from the third - 0.25%, from the fourth - 0.5%. Their performance is 4: 3: 2: 1 respectively. Taken at random item was standard. Find the probability that it is made on the second machine.

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