At the craft store, Mark bought a bag of blue and brown marbles. The bag contained 20 marbles, and 30% of them were blue. How many blue marbles did Mark receive?

50 points~ ! i have to turn this in tomarrow

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

Which equation is equivalent to the given expression? -(1/2y+1/4) a. -1/4(1+2y) b. 1/4(2y-1) c. -2(1/4y-1/8) d. 2(1/8-1/4y)