Final answer:
To determine the number of model planes Jamie has, we set up the equation x + 6x = 112, where x represents Jamie's planes. Solving this equation, we find that Jamie has 16 model planes.
Step-by-step explanation:
Jamie and Sara have a total of 112 model planes together. According to the problem, Sara has 6 times as many model planes as Jamie. Let's assume Jamie has x model planes. Thus, Sara would have 6x model planes. The total amount of planes they have together is 112, which is the sum of the planes Jamie has and the planes Sara has. So we can write the equation:
x + 6x = 112
Merging the terms gives us 7x = 112, and then dividing both sides by 7 to solve for x yields:
x = 112 / 7
x = 16
Therefore, Jamie has 16 model planes.