Answer: B) $47/week
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Explanation:
Because the graph goes through the origin, we can simply divide the y value over the x value. Do so for any point on the diagonal line.
For example, picking (x,y) = (2, 94) leads to k = y/x = 94/2 = 47 being the constant of proportionality and also the amount of savings per week.
You can think of it like this:
2 weeks = $94 in savings
2/2 weeks = $94/2 in savings ... divide both sides by 2
1 week = $47 in savings
leading to the savings rate of $47 per week
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Side note: This linear equation is y = 47x. It is in the form y = kx with k = 47. It is a direct proportion equation. The constant of proportionality is also the slope. All direct proportion equations are linear and go through the origin.
