Question 428546
son's age	x											
father's age	3x								
10 years later										
son's age x+10									
father's age 3x+10							
father's age	2times older										
3x+10=2(x+10)	
3x+10=2	x+20			
x=20-10				
x=10	son's age							
x+20=30	years father's age