Solving Current in a Cell: Use I = V/R to Find 2/3

[calculator20]

Trying to work out how to do this. I know the answer is B but don't know how.

Internal resistance is negligible so I assume I just use I =V/R. I've tried using sample values for R eg 5 and V =10V giving I as 1.3 but am no closer to 2/3. What am I missing?

 

[nasu]

Can you show how did you do it with sample values? How do you calculate the current?

 

[calculator20]

If R=5ohms

1/5+1/5=0.4

1/0.4 = 2.5 ohms in parallel

2.5 + 5 = 7.5 ohms total

If v is 10v

I = v/R = 10/7.5 = 1.333333

 

[nasu]

And this is compatible with answer b, isn't it?
Try to calculate 2e/3R. How much is it?

You have the right idea. Now just do the same thing with symbols rather than numbers.
What is the equivalent resistance, in terms of R?

 

[calculator20]

Got it! Many thanks