Answer:
and 
Step-by-step explanation:
Given:
Equation 1:

Simplifying the above equation by dividing both sides by 100


Equation 2:

Simplifying the above equation by dividing both sides by 400.


Now the system of equation is:
(1a) 
(2a) 
Solving by elimination
Multiplying equation (2a) with 

(2b) 
Adding equations (1a) and (2b) in order to eliminate 

+ 
We get 
∴ 
Plugging
in equation (2a).

Adding
both sides.

∴ 
Answer:

Step-by-step explanation:



or

Answer:
432
Step-by-step explanation:
Answer:
Check the explanation
Step-by-step explanation:
Since each and every one of the 4 hallways is equally likely then

Now, if he chooses H1 he escapes after 12 minutes then

If he chooses H2 then he wastes 10 minutes and then he is again in the same starting
position so he expects to escape in E(T) minutes, then

Analogously, if he chooses H3 then he wastes 40 minutes and then he is again in the same starting
position so he expects to escape in E(T) minutes, then

Therefore

So we have

Therefore he is expected to escape in 72 minutes
Answer: think were a week late
Step-by-step explanation: