Question 426425
brother's age	x											
John's age	x+6									
4	years later										
brother's age	x+4									
John's age	x+6+4=x	+10		
Jack is 2 times older										
x+10=2(x+4)	
x+10=2x	+8			
2x-1x=10-8				
x=2							
/1									
x=2	brother's age							
x+6	=8years	John's age