Answer: 0.3758
Explanation:
Given : The probability that a milk container is underweight throughout of packaging line:
![p = 0.20](https://img.qammunity.org/2020/formulas/mathematics/college/uv41lseb52v1goz279r9tmda6jdkb8ezvf.png)
The number of containers : n= 10
The formula binomial distribution formula :-
![^nC_rp^(n-r)(1-p)^r](https://img.qammunity.org/2020/formulas/mathematics/college/uz7dt3ihub9e8df4uh45k9zvcu7mcpg3e9.png)
The probability that at least nine milk containers in a box are properly filled is given by :-
![P(X\geq9)=P(9)+P(10)\\\\=^(10)C_9(0.2)^(10-9)(1-0.20)^9+^(10)C_(10)(0.2)^(10-10)(1-0.2)^(10)\\=10(0.2)(0.8)^9+(1)(0.8)^(10)\\=0.3758096384\approx0.3758](https://img.qammunity.org/2020/formulas/mathematics/college/w61x3cuq1cf2w5xertg31troexbdopzsh4.png)