## anonymous one year ago 1. Find the sum of the geometric sequence –3, 15, –75, 375, … when there are 8 terms and select the correct answer below. –195,312 195,312 292,968 –292,968

1. freckles

you can add the 8 terms up like it is or you can use a formula if you wish

2. anonymous

2. Finn bought a yoyo from a company that claims that, with each retraction, the string rolls up by 80% of the original length. He sets up a tape measure and throws the yoyo 3 times. His data are charted below. Throw Length of string (feet) 1 3 2 2.4 3 1.92 Finn wants to find the sum of the length of string after 10 throws. What is the sum of the lengths, rounded to the nearest hundredth? 13.39 feet 15.00 feet 4.46 feet 0.40 foot 3. Evaluate S5 for 300 + 150 + 75 + … and select the correct answer below. 18.75 93.75 581.25 145.3125

3. freckles

$S_n=\frac{a_1(1-r^n)}{1-r} \\ \text{ where} n=8 \text{ since you want to find the sum of the first 8 terms }$

4. anonymous

@freckles just add the terms that's it?

5. anonymous

@freckles or did you mean multiply?

6. freckles

7. freckles

you are to find the sum not the product

8. freckles

you have to find the other 4 terms though if you do it that way

9. freckles

but I would just use the formula because it is quicker to me

10. freckles

i must go good luck

11. anonymous

@freckles thanks