The mean age of 5 people in a room is 39 years. A person enters the room.
The mean age is now 40.
What is the age of the person who entered the room?

What is the value of x in the equation 2(x-4) = 4(2x + 1)?

In a city, 6th and 7th avenues are parallel and the corner that the pizza palace is on is a 54° angle. what is the measure of the angle that is made with 7th ave and broadway on the corner of the shake hut?

There are a total of 75 students in the robotics club and the science club. the science club has 11 more students than the robotics club. how many students are in the science club?