Five years ago father was thrice son's age. 10 years hence father will be twice sons age, find present age ( use two variables)

2 answers

f-5 = 3(s-5)
f + 10 = 2(s+10)
----------------
-15 = 3(s-5) - 2(s+10)

-15 = 3s - 15 -2s -20

20 = s
then
f-5 = 60 -15
f = 50
5 year ago.father age was9 time of his son.after 10 year from now father's age will be thrice of his son age.find the present of each one?