How to show a number is rational in two ways?

17 in long 1.3 ft wide and 8in high what is the volume

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?