I need help with Math I'm not sure how to do it ​

Sole with work in 10 years, the average number of hours of tv watched per week by teenagers dropped from 23.9 to 21.4. find the percent of change.

What is the mean of the data set 125, 141, 213, 155, 281

Currently, the largest cruise ship has a tonnage of 225,282 gross tons (gt). which of the following is a reasonable estimate for the tonnage of this cruise ship? a. 2 × 10^5 gt b. 2 × 10^6 gt c. 2 × 10^-5 gt d. 2 × 10^-6 gt