Which option best describes the main behavior that economics studies?

Amathematical approximation called the rule of 70 tells us that the number of years that it will take something that is growing to double in size is approximately equal to the number 70 divided by its percentage rate of growth. thus, if mexico's real gdp per person is growing at 7 percent per year, it will take about 10 years(=70/7) to double. apply the rule of 70 to solve the following problem. real gdp per person in mexico in 2005 was about $11,000 per person, while it was about $44,000 per person in the u.s. if real gdp per person in mexico grows at the rate of 5 percent per year: how long will it take mexico's real gdp per person to reach the level that the united states was at in 2005? (hint: how many times would mexico's 2005 real gdp per person have to double to reach the u.s.'s 2005 real gdp per person?

Mai and chuck have been divorced since 2012. they have three boys, ages 6, 8, and 10. all of the boys live with mai and she receives child support from chuck. mai and chuck both work and the boys need child care before and after school. te boys attend the fun house day care center and mai paid them $2,000 and chuck paid them $3,000. mai's agi is $18,000 and chuck's is $29,000. mai will claim two of the boys as dependents. she signed form 8332 which allows chuck to claim one of the boys. who can take the child and dependent care credit?

Consider two similar industries, portal crane manufacturing (pcm) and forklift manufacturing (flm). the pcm industry has exactly three incumbents with annual sales of $800 million, $200 million and $100 million, respectively. the flm industry has also exactly three incumbents, with annual sales of $500 million, $450 million and $400 million, respectively. which industry is more likely to experience a higher level of rivalry?