Hugo decided to pay $2 a week to his brother to buy a bicycle. The equation $y-10=-2(x-10)$ models the amount of money he owes for the bike, where $x$ is the number of weeks and $y$ is the amount of money he still needs to pay.
The problem provides a linear model for the amount of money owed for a bicycle. The equation is given as \(y - 10 = -2(x - 10)\), where \(y\) represents the amount of money owed in dollars and \(x\) represents the number of weeks elapsed. We are tasked with determining two values: the total cost of the bicycle (which corresponds to the amount owed at \(x=0\)) and the number of weeks required for Hugo to finish paying off the debt (which corresponds to the time when the debt \(y=0\)).
To make the equation easier to interpret, we convert it into the slope-intercept form, \(y = mx + b\), where \(m\) is the rate of payment and \(b\) is the initial cost. Starting with \(y - 10 = -2(x - 10)\), we distribute the \(-2\):
\[y - 10 = -2x + 20\]
Adding 10 to both sides yields:
\[y = -2x + 30\]
In this form, we can clearly see the initial value is \(30\) and the weekly reduction is \(2\).
To find the initial cost of the bicycle, we evaluate the amount owed \(y\) at the start, which occurs at \(x = 0\) weeks. Substituting \(x = 0\) into our simplified equation \(y = -2x + 30\):
\[y = -2(0) + 30 = 30\]
Therefore, the bicycle cost \(\$30\).
To find out when the debt is fully paid, we need to find the number of weeks \(x\) such that the amount remaining to be paid \(y\) is \(0\). Setting \(y = 0\) in our equation \(y = -2x + 30\):
\[0 = -2x + 30\]
Rearranging to solve for \(x\):
\[2x = 30\]
\[x = 15\]
Hugo will finish paying for the bike in 15 weeks.
This linear model is a fundamental tool for financial planning, such as budgeting for a purchase or managing a loan. By modeling debt as a linear function \(y = mx + b\), individuals can easily predict when their remaining balance will reach zero or identify how much they started with. Such models are essential for tracking savings progress, calculating time-to-completion for projects, or managing installments in everyday life.