Question 515993
Let
Present age of Mr. Jackson = j
Present age of Son = s




Mr. Jackson is 13 years less than three times as old as his son. 
j=3s-13........(1)
Six years ago he was fourteen years more than twice as old as his son was then.
j-6=2(s-6)+14
j-6=2s-12+14
j-6=2s+2
j=2s+2+6
j=2s+8..............(2)
Put the value of j from (1) to (2)
3s-13=2s+8
3s-2s=8+13
s=21
Put the value of s in (1)
j=3s-13........(1)
j=3(21)-13
j=63-13
j=50


Present age of Mr. Jackson = j = 50 years old
Present age of Son = s = 21 years old