A pianist plans to play 4 pieces at a recital from her repertoire of 20 pieces, and is carefully considering which song to play first, second, etc. to create a good flow. How many different recital programs are possible?

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

Successful implementation of a new system is based on three independent modules. module 1 works properly with probability 0.96. for modules 2 and 3, these probabilities equal 0.95 and 0.90. compute the probability that at least one of these three modules fails to work properly.

The random variable x is defined as the number marking the sector in which the arrow lands when the spinner in the diagram is spun once.