Answer:
79.77%
Step-by-step explanation:
P(X≥120) = normalcdf(120,1e99,130,12) = 0.7976716754 ≈ 0.7977 = 79.77%
Therefore, about 79.77% of operations last at least 120 minutes
Answer:
The solution for this system is: 
Step-by-step explanation:
The problem states that we have to solve this system by the elimination method
In the elimination method, we transform the system in such a way that one variable can cancel each other. With this, we find the result of the other variable. Then, we can replace the variable we found in any of the equations, and we have the value of the variable that we had initially canceled.
In this problem, we have the following system:


If we add equations 1) and 2), the variable x is going to be eliminated





Now, we can replace the value of y in any of the equations, to find x:
I will replace in equation 2)





The solution for this system is: 
Answer:
£1 : £0.43
Step-by-step explanation:
So to make the ratio, you need the amount of money spent on advertising and the money spent on its website
Website money = £0.43
Advertising money = £1
£1 : £0.43