Each candidate in a tender is fluent in at least one out
of two required languages (English and French). There are
\(20\) candidates fluent
in English and \(14\)
candidates fluent in French. From these amounts
\(10\)
candidates are fluent in both languages. How many candidates are there in the
tender?
There are four paths from a city to the top of nearby mountain. Find the number of
possible treks from the city to the mountain and back, if it is required to use one
path up and another one down.