Question 1174605

a man  is 6 times old as his son. twenty years later he will be twice as old as his son find the man age when his son was born?
<pre>Let son's age be S
Then father's is: 6S
We then get: 6S + 20 = 2(S + 20)
6S + 20 = 2S + 40
6S - 2S = 40 - 20
4S = 20
Son, or {{{highlight_green(matrix(1,6, S, "is:", 20/4, "=", 5, years-old))}}}

That makes the father, 30. 
Difference in ages/Age of father when son was born: {{{highlight_green(matrix(1,3, 30 - 5, "=", 25))}}}</pre>