A crew team took 40 minutes to row 4 km up the river. It took them 30 minutes to row back the same distance in the direction of the current. Everyone rowed with the same intensity both ways. What is the speed of the current measured in km per hour?

Asphere has a diameter of 10 in. what is the volume of the sphere?

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

I'm marking the brainliest and it's 15 points