Which of the following shapes is considered to be a 2 dimensional
figure?
A. A cylinder
B. A cube
C. A pyramid
D. A circle

Ms. sutton recorded the word counts and scores of the top ten essays in a timed writing contest. the table shows her data. how does the word count of an essay relate to its score in the contest? word count tends to decrease as the score decreases. word count tends to increase as the score decreases. word count tends to remain constant as the score decreases. word count has no apparent relationship to the score of the essay.

Asmall (but heavy) particle placed in a glass of water will follow a zigzag motion because the particle will bounce off of the water molecules it meets. this is called brownian motion. a physicist simulates this on a computer, by varying the distance a particle can travel (called the mean free length), on average, before it collides with a water molecule and assigning the change in motion to be one of 8 directions, each with a similar probability. by running the simulated particle (with the same mean free length) many times she determines that it should take 15 seconds, on average, for the particle to fall to the bottom, with a standard deviation of 1.5 seconds. next she lets a real particle fall through a glass of water and finds that it took 18 seconds. what does she conclude, and why?

How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid in order to get a 40% solution of acid?