Arturo has completed 27 math problems, which is 75% of the assignment. How many problems total did he have to complete? I need help!

Recall that the owner of a local health food store recently started a new ad campaign to attract more business and wants to know if average daily sales have increased. historically average daily sales were approximately $2,700. the upper bound of the 95% range of likely sample means for this one-sided test is approximately $2,843.44. if the owner took a random sample of forty-five days and found that daily average sales were now $2,984, what can she conclude at the 95% confidence level?

Captain umaima has a ship, the h.m.s. khan. the ship is two furlongs from the dread pirate nadia and her merciless band of thieves. the captain has probability 3/7 of hitting the pirate ship. the pirate only has one good eye, so she hits the captain's ship with probability 2/5. if both fire their cannons at the same time, what is the probability that the captain hits the pirate ship, but the pirate misses.

Find the solution of this system of equations -7x+y=-20 9x-3y=36