Answer:
f(3) = 362.32 Hz
Step-by-step explanation:
the formula of frequency of open pipe is
f(n) = (n+1)v/2L
n = 0,1,2,3,... (the order)
0 for the first
1 for the second
v = speed of sound
L = the lenght of pipe
f(3) = (2+1) * 343 / 2 * 1,42
f(3) = 3 * 343 / 2.84
f(3) = 362.324 Hz (or you can write 362.32 Hz