Please help I don’t understand this..

Last saturday, the museum box office sold 281 tickets for a total of $3,954. adults ticket cost $15, and students ticket cost $12. how many of each kind of tickets were sold?

Aplane flies around trip to philadelphia it flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour if the total trip takes 6.5 hours how many miles does the plane fly round trip

Student price tickets to a movie are $1 and non student tickets are $2 . 350 tickets are sold and the total amount made is $450. there were 250 student tickets sold . true or false .