Calculate the amount, in grams, of an original 300 gram sample of potassium 40 remaining after 3.9 billion years. a. 300
b. 150
c. 75
d. 37.5​

Use the empirical rule. the mean speed of a sample of vehicles along a stretch of highway is 70 miles per hour, with a standard deviation of 4 miles per hour. estimate the percent of vehicles whose speeds are between 66 miles per hour and 74 miles per hour. (assume the data set has a bell-shaped distribution.)

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

After a big snowfall, you take your favorite rocket-powered sled out to a wide field. the field is 195 m across, and you know that your sled accelerates at a rate of 3.65 m/s2 when the rocket is on. how much time will it take the sled to cross the field starting from rest, assuming the rocket is on the whole time?