HI experts!!

need working out for these questions I couldn't do, answers don't need to be thorough, just working out is fine thanks!

\f[a] The percentage of defective transistors produced by afactorg.r is 15%. If a sample of transistors are randomly selectedI calculate the probability that exactly 3 transistors in this sample will be defective. [b] The number of trucks arriving at a weighing station follow a Poisson distribution with an average of 2 loaded trucks per day. Determine the probability that exactly 1IZI trucks will arrive at the weighing station in a particular week. [1:] Assume that the resistance of a certain type of resistors is normally distributed with a mean of 250 ohms and astandard deviation of 15 ohms. 1What percentage ofthe resistors of this type will have resistance aboye ETD ohms