how to concatenate two string in grafana metrics

Question

how to append two variable inside vector,

[30d] should be replaced with [${days}${consd}]

my actual query (part of the query)

method=~"[[Method]]",le="+t"}[30d])) * 100

here i want replace the 30d with two grafana variable say one

grafana variable "days" as text box defaulted with 40, which will be edited by user.
grafana variable "consd" as constant defaulted with value "d".

now i need to update the above query like below but its not working its just taking only the first value.

method=~"[[Method]]",le="+t"}[${days}${consd}])) * 100

Answer 1

method=~"[[Method]]",le="+t"}[${days}d])) * 100