SOLUTION: Sarah, who is 20 years old, is 4 times as old as her brother. How old will Sarah be if she is twice as old as her brother?

Question 851649: Sarah, who is 20 years old, is 4 times as old as her brother. How old will Sarah be if she is twice as old as her brother?
Answer by josh_jordan(263) (Show Source): You can put this solution on YOUR website!
We know Sarah is 20 and she is 4 times as old as her brother. Therefore, her brother is 5. Now, we can just add years to Sarah and her brother's age to find out when she will be twice as old as he will be:

In 1 year: Sarah = 21, Brother = 6
In 2 years: Sarah = 22, Brother = 7
In 3 years: Sarah = 23, Brother = 8
In 4 years: Sarah = 24, Brother = 9
In 5 years: Sarah = 25, Brother = 10
In 6 years: Sarah = 26, Brother = 11
In 7 years: Sarah = 27, Brother = 12
In 8 years: Sarah = 28, Brother = 13
In 9 years: Sarah = 29, Brother = 14
In 10 years: Sarah = 30, Brother = 15

As you can see, in 10 years, Sarah will be twice as old as her brother. So, Sarah will be 30 years old when she is twice as old as her brother.
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