I flip a fair coin independently n times For each heads you

I flip a fair coin, independently, n times. For each heads, you win $3, whereas for each tails, you lose $1. Define the random variable X to be the amount of dollars that you win. What is the expected value of X?
(a) n/2
(b) n
(c) 3n/2
(d) 2n

Please explain briefly?

Solution