PLEASE HELP! Expected value finite math question

Question

Stereo speakers are manufactured with a 0.25 probability of being defective. Five speakers are randomly selected. Let the random variable X be defined as the number of defective speakers.  

Find the expected value.

Answer 1

There is a probability of 0.25 that a given speaker is defective. So for a given speaker, the expected value of defective speakers is 0.25. If there are five randomly selected speakers, the expected value is 5*(0.25) = 1.25