Help need to know how to get the answer and the answer. I tried and the answer I got was 24

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

Can someone me with my math problem pls my teacher is on my back about this

Given: △abc, bc> ac, d∈ ac , cd=cb prove: m∠abd is acute