Answer:
2.22 hours
Explanation:
If Sally can paint the office by herself in 5 hours, we can say that in one hour she paints 1/5 of the office.
On the other hand, Lucy paints the office in 4 hours, which means that, in 1 hour she paints 1/4 of the office.
Therefore, to know how much they would paint per hour working together, we are going to sum up the fractions they paint per hour:
Therefore, working together they will paint 
of the office in one hour.
Now we can establish a rule of three: if they paint 0.45 of the office in 1 hour, how long (x) will it take them to paint 1.0 of the office?
And therefore 
Therefore, it will take them 2.22 hours to paint the office working together.
Jet stream and cold front of course
The answer is A, because an HOV lane is used for people with 2 or more persons in the vehicle. There is usually a set time that people can use the HOV lane. It was made like that because people thought that when somebody would carpool or drive a coworker to their job, it would be a much faster and convinent way because the speed limit is higher in the HOV lane.
Answer:
Combustion engine
Explanation:
The combustion engine were some of the most significant and very far technologies of the Industrial Revolution. This was first presented in 1878 and was propelled by gas and air, making it unsuitable for large public use. During the Industrial Era, the combustion engine was perhaps the most efficient, both in the early years and even in the long run.
