You can put this solution on YOUR website!
If Jon is 8 then Mr Dawson is 8*5=40 years old.
Lets say in x years, Mr Dawson will be 3 times as old as Jon, then
(we divided right side by 3 in order to make the equations even). Now to get rid of the fraction we multiply both sides by 3,
subtract x from each side
subtract 24 from each side
divide both sides by 2
So in 8 years :)