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Nine Years ago, Frank was half as old as Marilyn. Now his age is two thirds her age. Find their ages now. WITH WORK PLEASE
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Let F be the Frank's present age, M be the Marilyn's present age.
9 years ago Frank was (F-9) years old, while Marilyn was (M-9) years old.
The condition says
F - 9 = . (1) ("Nine Years ago, Frank was half as old as Marilyn")
Now his age is two thirds her age:
F = . (2)
Substitute (2) into equation (1) replacing F. You will get
= .
You have a single equation for single unknown M. To solve it, multiply both sides by 6 to rid of denominators. You will get
4M - 54 = 3*(M-9),
4M - 54 = 3M - 27,
4M - 3M = -27 + 54,
M = 27.
So, we found Marilyn present age is 27 years.
Then from (2) Franklin 18 = years old.
Solved.
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 word problems".