Mark and his brother David are fighting over a toy airplane while playing their yard. Mark grabs the plane and takes off running at rate of 7.5 miles per hour. One minute after Mark starts running, David starts to chase him at rate of 9mph. How long will David to reach Mark and how far will they have run?

Diane owes $387 to her brother. if she debits her bank account $161.25 a month to pay him back, how many months will it take her to pay off the debt?

Polygon hh is a scaled copy of polygon gg using a scale factor of 1/4. polygon h's area is what fraction of polygon g's area?

In a test for esp (extrasensory perception), the experimenter looks at cards that are hidden from the subject. each card contains either a star, a circle, a wave, a cross or a square.(five shapes) as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. when the esp study described above discovers a subject whose performance appears to be better than guessing, the study continues at greater length. the experimenter looks at many cards bearing one of five shapes (star, square, circle, wave, and cross) in an order determined by random numbers. the subject cannot see the experimenter as he looks at each card in turn, in order to avoid any possible nonverbal clues. the answers of a subject who does not have esp should be independent observations, each with probability 1/5 of success. we record 1000 attempts. which of the following assumptions must be met in order to solve this problem? it's reasonable to assume normality 0.8(1000), 0.2(1000)%30 approximately normal 0.8(1000), 0.2(1000)% 10 approximately normal srs it is reasonable to assume the total number of cards is over 10,000 it is reasonable to assume the total number of cards is over 1000