Problem #$1(25\%,$ must be done by hand$)$: Ideal Channel Impulse Response

Assume that the relative channel response between a transmitter and a receiver in an ideal channel is given by the amplitudes below. Assume that ${}_n=0$ for all $n.$

Compute the mean channel delay, $\frac{?}{\text{b}\text{a}\text{r}}(),$ and the RMS delay spread, ${}_{rms},$ both in $s,$ for this channel response, and also compute the Coherence Bandwidth, $B_C,$ in kHz $.$