Help please i dont understand any of this

On tuesday, a local hamburger shop sold a combined total of 375 hamburgers and cheeseburgers. the number of cheeseburgers sold was two times the number of hamburgers sold. how many hamburgers were sold on tuesday?

If y+3y+5y=−18 y + 3 y + 5 y = − 18 , then what is the value of y y ?

There is a 9% chance that a booked gig will get cancelled. if you have 4 gigs in a row, what is the probability none of them will get cancelled!