SOLUTION: Beth is 10 years old, and her dad is 40 years old. How many years ago was Beth 1/7 as old as her dad?

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Question 78802: Beth is 10 years old, and her dad is 40 years old. How many years ago was Beth 1/7 as old as her dad?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Beth is 10 years old, and her dad is 40 years old. How many years ago was Beth 1/7 as old as her dad?
:
Let x = number years since Beth was 1/7 of her Dad's age
:
At that time Dad's age will be 7 times Beth's age
:
(40 - x) = 7(10 - x)
:
40 - x = 70 - 7x
:
7x - x = 70 - 40
:
6x = 30
:
x = 30/6
:
x = 5 years ago:
:
DAd was 35 and Beth was 5