What is ln x+2 ln y-ln z written as a single log

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

Angela took a general public aptitude test and scored in the 88th percentile for aptitude in accounting. what percentage of the scores were at or below her score?

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?