ruby bought $18 worth of donuts and cookies. each donut costs $1 and each cookie costs $1.50. she bought a total of 15 donuts and cookies all together. graphically solve a system of equations in order to determine the number of donuts, x, and the the number of cookies, y, that ruby bought.

Atextile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms. the company wishes to test the hypothesis upper h subscript 0 baseline colon mu equals 12 against upper h subscript 1 baseline colon mu less-than 12 using a random sample of n equals 4 specimens. calculate the p-value if the observed statistic is x overbar equals 11.8. round your final answer to five decimal places (e.g. 98.76543).