Kim decides to download some new music. he downloaded 6 albums and 7 singles, and his total was $68. the next day she purchased more music from the same retailer and downloaded 2 more albums and 9 singles for a total of $36. assuming that all albums and singles are the same price, how much did he spend on each album and each single? write a system of equations to represent this situation. then solve for the solution using the elimination method.

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 the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?

Ann and betty together have $60 ann has $9 more than twice betty’s amount how much money dose each have