Work out (5X10^3) x (9X10^7) answer in standard form plz

Andrea went to the store to buy sweater that was on sale for 40% off the original price it was then put on clearance an additional 25% off the sale price she also use a coupon that saved her an additional five dollars and j did not spend more than $7.60 for the sweater what are the possible values for the original price of the sweater?

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?