Solving Capacitor Circuit: 3uF, 6uF, 2uF, 4uF & 90V

[brittydagal]

Homework Statement

the question - http://tinypic.com/r/14l37yv/6
its a little hard to see but the top left capacitor is 3 uF, the one to its right *(in series) is 6 uF, the one on the bottom left is 2 uF, the one in series with the 2uF one is 4 uF and on the bottom is 90V.

Homework Equations

V = IR
C = Q/V
Series = same Q
Parallel = Same V

The Attempt at a Solution

part 1 of my work - http://tinypic.com/r/jtpd0p/6
part 2 of my work - http://tinypic.com/r/2lkbdww/6

 

[mfb]

How did you calculate (a)? It is wrong. I think you forgot to take inverse values somewhere. Working with units would help here.
As additional check, you could calculate the potential difference at the top left capacitor. The sum of that and your result in (b) should add up to 90, but it does not.

 

[brittydagal]

UGHH i totally see what i did. dangit
i was doing
1/3 + 1/6 = .5
but I am pretty sure its suposed to be
1/3 + 1/6 = 1/x ----> which would make the combination of the top to uF equal 2 instead

 

[brittydagal]

..so would A) equal 3.3 uF then?

 

[brittydagal]

And was I doing B on the right track than? just my numbers were messed up?

 

[mfb]

10/3µF, which is about 3.3µF, right.
The concepts for b-d are fine.

 

[brittydagal]

It worked out perfectly :) thanks