Two green faucets take 4 hours together to fill a deposit. two other blue faucets take half together. how long does it take to fill the tank with a blue and a green tap together?

Someone this asap for a group of students attends a basketball game. * the group buys x hot dogs at the concession stand for $2 each. * the group buys y drinks at the concession stand for $3 each. the group buys 29 items at the concession stand for a total of $70. how many hot dogs did the group buy?