$[1]$: import math

$[36]$: def TruckAvrgSpeed $($d$,$ t$)$:

avg $=0$

Max$\_$Speed$\_$Way $=-1$

$[38]$: for i in range$($len$($d$))$:

if distances $[$i$]/$ times $[$i$]>$ avg:

avg $=$ d$[$i$]/$ t$[$i$]$

Max$\_$Speed$\_$Way $=$ i $+1$

return Max$\_$Speed$\_$Way

NameError

Traceback $($most recent call last$)$

Cell In$[38],$ line $1$

$--->1$ for i in range$($len$($d$))$:

$2$ if distances $[$i$]/$ times $[$i$]>$ avg:

$3$ avg $=$ d$[$i$]/$ t$[$i$]$

NameError: name $\text{'}$d$\text{'}$ is not defined

$[]$: why d is not defined please help me