Acertain element has a half life of 2.5 billion years. a. you find a rock containing a mixture of the element and lead. you determine that 55? % of the original element? remains; the other 45? % decayed into lead. how old is the? rock? b. analysis of another rock shows that it contains 5? % of its original? element; the other 95? % decayed into lead. how old is the? rock?

Need an artist designed a badge for a school club. figure abcd on the coordinate grid below shows the shape of the badge: the badge is enlarged and plotted on the coordinate grid as figure jklm with point j located at (2, -2) and point m is located at (5, 4). which of these could be the coordinates for point l? a. (2, 4) b. (8, 4) c. (5, 1) d. (5, 7)

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

X^2/100+y^2/25=1 the length of the major axis is: a)5 b)10 c)20