2004 AMC 10A Problem 11

A company sells peanut butter in cylindrical jars. Marketing research suggests that using wider jars will increase sales. If the diameter of the jars is increased by 25\% without altering the volume, by what percent must the height be decreased?

\mathrm{(A) \ } 10 \qquad \mathrm{(B) \ } 25 \qquad \mathrm{(C) \ } 36 \qquad \mathrm{(D) \ } 50 \qquad \mathrm{(E) \ } 60

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.