Question 437671
cory's age = 20% of father's age
so father is 5 times cory's age
let cory's age = x
father's age = 5x

42	years later									
Cory's age x+42								
father's age	5x+42	
If Cory 's age = 2/3 of father's age then father is 1.5 times cory's age					
father's age	1.5	times older									
5x+42=1.5(x+42)
5x+42=1.5x+63		
3.5x=63	-42			
3.5x=21						
/3.5								
x=6 Cory's age						
x+20=26	years		father's age