This is a geometric sequence because each term is a constant multiple, called the common ratio, of the previous term. In this case the common ratio, noted as "r", is:

8/-2=-32/8=128/-32=r=-4

The first term is -2

Any geometric sequence can be expressed as:

a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number.

Since we know r and a for this problem already we can say:

a(n)=-2(-4)^(n-1)

6 0

4 years ago

Sara and Jenny can both do flips in the air. The ratio of the number of flips Sara can do to the number of flips Jenny can do is

Snowcat [4.5K]

Wow! I never had problems this hard in middle school!

But you can do it!

First, we need to figure the number of flips Sara can do based on Jenny's.

Jenny = 120 and Sara - 120 x 3/8 (because she is only 3/8 of Sara's)

Calculate 120 x 3/8 = 45 flips

Now we know that Sara increased her amount of flips by 3 (45 +3 = 48)

And we know that Jenny decreased hers by 12 (120 - 12 = 108)

So now we have a ratio of 48:108, but we need to simplify that with factoring.

I am going to divide first by 2.

24:54

Then 2 again...

12:27

How about 3?

4:9

I think that is as far as we can go.

Sara is now doing 4 out of every 9 that Jenny does.

Check it!

108 (Jenny) x 4/9 = 48 (Sara) Yes! It checks.

8 0

4 years ago