Joint PMFs of Multiple Random Variables - Urgent Help

**It says my answers are incorrect. Can anyone help me please? What did I do wrong..?**

On a given day, your golf score takes values from range 100 to 109, with probability 0.1, independently from other days. Determined to improve your score, you decide to play on three different days and declare as your score the minimum X of the scores X1, X2, X3 on the different days.

- Calculate the PMF of X.

pX(107)=

pX(107)=comb(3,1)*0.1*0.3*0.3=0.027

Px(k)=P(X>k-1)- P(X>k)

Where P(X>k) = P(X1>k, X2>k, X3>k)=(109-k)^3*/(10^3) - pX(101)=

**pX(101)= comb(3,1)*0.1*0.9*0.9=0.243**; - By how much has your expected score changed as a result of playing on three days?

**If PX(100+i)=0.3*(1-i)^2 then E(X)=102.475**

If P(X.1 then E(X)=104.5 Difference=102.475-104.5=-2.025

Method's the same, just different numbers

The probability of the score 101 is still 0.1, but the probability of getting a larger score is now different. Larger scores include 102, 103, 104, 105, 106, 107, 108 and 109. There are 8 of them, so that likelihood is 0.8, instead of 0.2 for the last problem.

The method's the same, can you try it with the different numbers?