See the attached file.
A double walled straw with an outer diameter of ½" and an inner diameter of ¼" is placed in a glass of water as shown and described below:
a) Determine the volume of water in the 4" diameter by 4" high cup of water
b) Determine how high the water will rise in both the outer layer of straw and the inner layer of the straw ---- and describe why? Describe the equations in detail to be used to determine capillary rise in the straw.
The explanations are in the attached pdf file.
There are some explanations on the web, such ...
This solution provides calculations for determining volume of water and amount of capillary rise.