Let m represents the number of hours the buries spent before 11p.m
Let n represent the number of hours the buries spent after 11p.m
m + n = 5 -----------equation (1)
5m + 7.5n = 35 -------equation (2)
Using Gaussian elimination method to solve the simultaneous equations, we have
[tex]\begin{bmatrix}{1} & {1} & {5} \\ {5} & {7.5} & {35} \\ {} & {} & \end{bmatrix}-\begin{bmatrix}{\square} & {\square} & {\square} \\ {\square} & {\square} & {\square} \\ {\square} & {\square} & {\square}\end{bmatrix}[/tex]The value of m = 1, while n = 4
This implies the buries spent 4 hours after 11 p.m
That means they come home by 3 a.m
