With reference to Exercise 3.85, find the distribution function of the random variable X and plot its

Question:

With reference to Exercise 3.85, find the function of the random variable X and plot its graph.
In exercise
A coin is biased so that heads is twice as likely as tails. For three independent tosses of the coin.
Use the function of X to find
(a) P(1< X ≤ 3);
(b) P(X > 2).
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...