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?

Yes
No

Answer 1

Yes

Explanation:

Let's consider what Adrian does for a few weeks, that is, we will make a table where we can see the behavior of the savings with respect to the weeks that pass:

time (week) savings ($)

0 28

1 43

2 58

3 73

4 88

5 103

and if we continue doing we see that it has a similar behavior, and the equation would be:

s = 15 * m + 28

where s are the savings and m the number of months, which means that 15 is that constant of proportionality and therefore they are proportional.