Try see how you react?

Conclude that you are young or old?

Find numbers from 1 to 50

Respectively and very fast

Compare:

20-29 seconds: very clever

30-39 seconds: awesome

40-59 seconds: professional

60-79 seconds: normal

80-99 seconds: You're getting old

100-150 seconds: You are old

More than 150 seconds: too tired

By the way, under 20 seconds Genius