Question

At the beginning of the year, Adrian's savings account balance was $28. Each week, he deposits another $15 into that account, and he doesn't spend any of his savings.

Is his savings account balance proportional to the number of weeks since the start of the year?

Answer 1

No, because 28 and 15 have no common numbers in multiplying. and if you graph those in a line graph it is not a straight line and in order to be proportional the graph line has to pass the origin and be a straight line.

Answer 2

The given condition is not proportional.

Explanation:

At the beginning of the year, Adrian's savings account balance was $28.

Let Adrian invests for 'x' weeks.

So, total amount will becomes :

`28+15x`

Since 4 weeks = 1 month, it will represent a linear equation only.

Linear functions have a constant rate of change and describe a straight line on a graph. So, this is not proportional.

The given equation is in the form y = mx + b, so its linear. For the equation to be proportional, it should be in the form of y = kx.