What is the diameter of the new pipe?

Question

The diameters of two water pipes of the same length are 6 in. and 8 in. A single pipe of the same length replaces the two pipes. The single pipe has the same volume as the two original pipes combined. What is the diameter of the new pipe?

Answer 1

Volume will be the same if the cross section of new pipe (pi.R^2) is equal to the sum two smaller sections (pi*(8^2+6^2).

 

 

That is;

 

R^2=8^2+6^2=100  ; and R=10(in)