In autumn a tree starts to shed its leaves. 2/5 of the leaves fall off in the first week, 1/2 of those remaining fall off in the second week, and 2/3 fall of in the third week.85 leaves now remain.
what fraction of leaves have fallen off at the end of:
a)the second week
b)the third week ?
how many leaves did the tree have to start with ?

the answer is 11.2 (i know i’m late)

irst, find the z score of a score of 80. this is given by the formula z = (x-u)/o, where x is the score, u is the mean, and o is the standard deviation. this gives

z = (80-78)/12 = 1/6 = .1667

now, find what percentile a z score of 1/6 correlates to in the normal distribution.

a z score of 1/6 = .1667 is equivalent to the 56.36th percentile of the distribution. so the probability a score is over this is 1-.5636 = .4364

the mean of a sample mean is equal to the original mean. however, the standard deviation of a sample mean is equal to the original standard deviation divided by the square root of n (sample size). so the new standard deviation is 12/sqrt(16) = 3.

the new z score is 80-78/3 = 2/3 = .667. this is equivalent to the 74.86th percentile. so the probability that the mean will be greater than this score is 1-.7486 = .2514.

well

44-3-3-3=35

35+4+4+4+4=51

so the ansewr would be 51 degreesat 7: 00

2500

step-by-step explanation:

2500 multiplied by 0.05 = 125