求助大神这几道题都没看懂啥意思！！

wyltele

1> Yes No No
1a: the variability means the variation of the population.
1b: the number is current month compare to proceding month
1c: change is 0.8

wyltele

2> offer 1: 175000; offer 2: 172700
190000-1250*12
194000-1775*12