Ken:
Ken's Age = 18
Elizabeth:
Elizabeth's Age = 2/3 x Ken's age
Elizabeth's Age = 2/3 x 18
Elizabeth's Age = 12
Clint:
-Note: At Clint's next birthday. So we need to subtract 1 from the age.
Clint's Age = (2 x Elizabeth's Age) - 1
Clint's Age = (2 x 12) - 1
Clint's Age = 24 - 1
Clint's Age = 23 right now
Hope this helps!! :)