The lowest note (fundamental note) emitted by any stretched string has a fundamental frequecy f_o = V/2l = 40Hz
The 1st overtone = 2f_o = 2 x 40 = 80Hz
2nd overtone = 3f_o = 3 x 40 = 120Hz
3rd overtone = 4f_o = 4 x 40 = 160Hz
4th overtone = 5f_o = 5 x 40 = 200Hz
Overtones between 40Hz and 180Hz are 80Hz, 120Hz, 160Hz = 3 Overtones