The graph is missing. So is the set of data point values. However, I can assume that as the temperature goes up, then so does the sale of ice cream. It's not a perfect relationship, but there is a strong positive correlation between the two variables.
A positive correlation means that as one variable increases, so does the other. Also, it means that if one variable decreases, then the other variable decreases as well. The two variables move in the same direction together.
If Ann can build the model in 3 hours, then in 1 hour she gets 1/3 of it done. Likewise, if Sam can build the model in 6 hours, then in 1 hour he gets 1/6 of it done. We are looking to find how long it takes when they combine their efforts, so we will add the two together and set it equal to 1/x, x being the number of hours it takes for both of them to get the whole job done. The equation then looks like this: 
. You will have to find the common denominator to add those fractions, and once you do, cross multiply to solve for x.
(cos Ф -cos Ф)² + (cos Ф + cos Ф)²
Firstly: (cos Ф -cos Ф)² = 0² = 0
Secondly :(cos Ф + cos Ф)² = (2cos Ф)². = 4. (cos Ф)² = 4cos² Ф
Mind you when you raise a cosine (or sin or tan...) to the n power, the n power should affect the cosine only and NOT the angle Ф
Multiply the original price by the percent of markup: 47x.045=2.115. Round: 2.115=2.12. Add original price and amount of markup: 47+2.12=49.12. Answer: $49.12 :)
