2595. For every 100 electric lamps of plant “A”, on average there are 83 standard, plant “B” - 63 standard. 70% of bulbs come from the factory “A” and 30% from the factory “B” to the store. The purchased light bulb was standard. Determine the probability that the light bulb is made at the factory "A."

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