In no time, they show one to be doubly right (3,5)
I believe the answer is:
two ticks
'be doubly right' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'in no time they show one' is the wordplay.
I cannot really see how this works, but
'no' could be 'o' (resembles 0 - 'no' can mean 'zero') and 'o' is located in the answer.
'time' could be 't' (abbreviation) and 't' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Another definition for two ticks that I've seen is " An instant".)