Solution:
Let the present age of Jackson be "x"
Therefore
Jackson's age 7 years ago = x - 7
And, Jackson's age after 20 years = x + 20
From given question,
Jackson’s age was 2/5 of the age he will be 20 years from now 7 years ago
[tex]\frac{2}{5} \times (x + 20) = x - 7\\\\2(x + 20) = 5(x - 7)\\\\2x + 40 = 5x - 35\\\\5x - 2x = 40 +35\\\\3x = 75\\\\Divide\ both\ sides\ by\ 3\\\\x = 25[/tex]
Thus present age of Jackson is 25 years old
