The sales totals at Macy's food store have increased exponentially over the month. Which of these best shows the sales in the first three months?

$1200 in the first month, $1220 in the second month, $1240 in the third month

$1200 in the first month, $1272 in the second month, $1344 in the third month

$1200 in the first month, $1285 in the second month, $1370.96 in the third month

$1200 in the first month, $1224 in the second month, and $1248.48 in the third month

Question

The sales totals at Macy's food store have increased exponentially over the month. Which of these best shows the sales in the first three months?

$1200 in the first month, $1220 in the second month, $1240 in the third month

$1200 in the first month, $1272 in the second month, $1344 in the third month

$1200 in the first month, $1285 in the second month, $1370.96 in the third month

$1200 in the first month, $1224 in the second month, and $1248.48 in the third month

kittiwitti1 · Answer

1. Is this multiple choice?
2. Where is the diagram? There should be a diagram to go along with this. The above is not sufficient information.

lena772 · Answer

It is multiple choice but there is no diagram

kittiwitti1 · Answer

Hmmm.
According to my calculator the exponents for any one of them would be a decimal...

kittiwitti1 · Answer

Let me try again on paper.

lena772 · Answer

Okay :)

agent0smith · Answer

Notice that in two of them, the $ amount increases the same each time... that's not exponential growth. So eliminate those 2.

kittiwitti1 · Answer

So the formula should be $$log_ax=y$$with y being the value in the second month... and x being 1200....We should find a with those known values.

lena772 · Answer

not A or B right @agent0smith

agent0smith · Answer

Correct, both linear.

kittiwitti1 · Answer

Sorry, wrong formula.$$a^x=y,~a^{1200}=y$$

lena772 · Answer

I'm leaning towards C

agent0smith · Answer

If exponential, there should be a common multiple between the numbers... divide one by the number before it to check there is

$1200 in the first month, $1285 in the second month, $1370.96 in the third month
for this one, 1285/1200 = 1.0708, but 1370.96 /1285 = 1.06689

agent0smith · Answer

the last one, 1224/1200 = 1.02, and 1248.48/1224 = 1.02

Which do you think is exponential?

kittiwitti1 · Answer

Throw the guy a medal for being awesome. :D
I could never do that.

lena772 · Answer

The last one of course.

agent0smith · Answer

Remember exponential means something like a^n... means you're multiplying by a over and over.

lena772 · Answer

Exponential is a ratio

agent0smith · Answer

GJ.

lena772 · Answer

Thank you so much!

kittiwitti1 · Answer

All credit goes to @agent0smith I barely did anything

anonymous · Answer

So is this D?

lena772 · Answer

yes.