The total cost of a catered meal for the Armstrong family reunion was to be split equally by the 20 people who came. Before the meal started, five more Armstrong's unexpectedly appeared. The total cost was shared equally among the 25 people, and so each person in the original group owed $4 less. What was the total cost of the catered meal?

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?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?