Simplify each expression. 7(n+3) I also need the work to be shown so i can also try to understand, thank you! :)

Somone me i want to know what 18 hours out of 24 hours in a fraction

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10