A shopkeeper bought 6 dozen pencils at $25 per dozen. He sold 2 dozen at $25 each and the remainder at $30 each. What was his percentage profit of the cost?

Can you me find the missing length. i attached an image.

How do you do the foil method with polynomials?

The computer that controls a bank's automatic teller machine crashes a mean of 0.6 times per day. what is the probability that, in any seven-day week, the computer will crash less than 5 times? round your answer to four decimal places