A guitar string is 90 cm long and has a fundamental frequency of 124 Hz. Where should it be pressed to produce a fundamatal frequecy of 186 Hz?

Explanation

The fundametal frequency of a string fixed at both ends is given by
`n = (1)/(2L) sqrt((T)/(mu))`
As F and mu are fixed
`(n_(1))/(n_(2)) = (L_(2))/(L_(1))`
`L_(2) = (n_(1))/(n_(2))L_(1) = (124)/(186) xx 90 = 60 cm`
Thus, the string should be pressed at 60 cm from an end.