SOLUTION: A father is three times as old as the son. Nine years ago the father was four times as old as the son find the present ages

Algebra.Com
Question 1053218: A father is three times as old as the son. Nine years ago the father was four times as old as the son find the present ages
Answer by ikleyn(52785)   (Show Source): You can put this solution on YOUR website!
.
A father is three times as old as the son. Nine years ago the father was four times as old as the son find the present ages.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

F = 3S,          (1)   ("A father is three times as old as the son")
F-9 = 4*(S-9)    (2)   ("Nine years ago the father was four times as old as the son")

Substitute (1) into (2). You will get

3S-9 = 4(S-9),

3S-9 = 4S - 36   --->  S = 27.

The son is 27 years old now. The father is 3*27 = 81 years old now.

Answer.  The son is 27 years old now. The father is 81 years old now.

There is a bunch of lessons on age word problems
    - Age problems and their solutions
    - A fresh formulation of a traditional age problem
    - Really intricate age word problem
    - Selected age word problems from the archive
    - Age problem for the day of April, 1
    - OVERVIEW of lessons on age problems
in this site.

Read them and become an expert in solving age problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Age problems".


RELATED QUESTIONS

A father is three times as old as the son. Nine years ago the father was four timesas old (answered by Fombitz)
A father is three times as old as the son.nine years ago the father was four times as old (answered by josgarithmetic)
A father is three times as old as the son .Nine year ago,the father was four times as old (answered by josgarithmetic)
A father is twice as old as his son. Twelve years ago the father was four times as old as (answered by lwsshak3)
A father is now three times as old as his son. 12 years ago he was six as old as his son. (answered by Maths68)
two years ago a father was four times as old as his son. three years from now the father... (answered by stanbon,ptaylor)
Two years ago, a father was four times as old as his son. Three years from now the father (answered by josgarithmetic)
a father is twice as old as his son..20 years before,the father was four times as old as... (answered by Narsinghchauhan8960103366)
Two years ago a father was four times as old as his son. Three years from now the father... (answered by ptaylor)