Please help simplify the expression

Aladder that is 30 ft long needs to reach 27 ft up a building. what should the angle of the vertical be?

On a piece of paper graph f(x)=5•(0.4)^x

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable