Question

In attempting to calculate the carrying capacity of a cylindrical pipe, Avery measured the outer diameter to be 2 inches, neglecting to notice that the pipe was one eighth of an inch thick. By what percent did Avery overestimate the carrying capacity of the pipe?

Answer 1

Volume of the pipe = πr^2l
Wrong measure = π x (2)^2 x l = 4πl
Correct measure = π x (2 - 2(1/8))^2 x l = 49/16πl
error = 4πl - 49/16πl = 15/16πl

% error = ((15/16πl) / 49/16πl) x 100% = 30.6%