A transit train from Boston to New York and a transit train from New York to Boston departed at the same time, 3:00 PM. The distance between New york station and Boston station is 280 miles. The speed of the transit train is 80 miles per hour. The speed of the passenger train is 80 miles per hour. What time will the two trains pass eachother?

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?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ac=26 and ch=8, find bh.

Solve the system of equations. x=-2y+1 and x+2y=9. show work