A geologist digs 5 feet down into the ground before taking a break. This process is repeated 3 times to create a hole that has a total depth of 15 feet. Which equation represents the hole's depth in relation to ground level?

A. -5 • 3 = -15
B. -3 • -5 = -15
C. -3 • 5 = 15
D. 5 • 3 = 15

•= multiplication

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

Me n o w. i need t h i s. 10 points

Ms.ortiz sells tomatoes wholesale. the function p(x)=-80x^2+320x-10, graphed below, indicates how much profit she makes on a load of tomatoes if she makes on a load of tomatoes if she sells them for 4-x dollars per kilogram. what should ms.ortiz charge per kilogram of tomatoes to make on a load of tomatoes?