Mr. X and Mr. Y, when work together, run out installing floor tiles a room in 6 day. When Mr. X works himself, he took time 5 days less than from Mr. Y who work alone. How much time Mr. X and Mr. Y take to spend this work itself without help?​

Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables