Saturday

December 20, 2014

December 20, 2014

Posted by **Jon** on Tuesday, March 4, 2008 at 12:18pm.

Sn=a1(1-r^n)/1-r

189=a1(1-1/2^3)/1-1/2

189=a1(-.5)/.5

189/-.25

a1=-756

- Math -
**Reiny**, Tuesday, March 4, 2008 at 12:57pmYOur third line is wrong

should be:

189 = a(1 - 1/8)/(1 - 1/2)

189 = a(7/8)/(1/2)

189 = a(7/4)

756 = 7a

108 = a

(check 108+54+27 = 189 !)

**Answer this Question**

**Related Questions**

math. HOW DO I CONVERT A DECIMAL TO A FRACTION - how do i convert a decimal to ...

Algebra 2 - 5+(-5/2)+(5/4) Sn=189 Find n for the given sum if the geometric ...

Geometry repost - "yes, except 20/36 / 21/x x= 189/5 = 37.8 seems to have a typo...

MATH - 1.32 + 0.987 + 3.07 = a-4.089 b-5.089 c-5.189 d-6.189 e-13.972 answer-5....

chem - Consider a Carnot engine operating between the temperatures of 300. K and...

chemistry - Temp - 650 Pressure - 760mm Hg mass - 0.927g volume - ? I need to ...

college physics - A 0.384 kg puck, initially at rest on a horizon- tal, ...

math - I am doing something wrong when I work this question. Can someone show me...

Statistics help Please - The table below reports birth weight and whether the ...

math - give the prime factorization of 189