SOLUTION: The difference between the ages of two sisters is 10 years. If 15 years ago the elder one was twice as old as the younger one. Find their present ages

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Question 884404: The difference between the ages of two sisters is 10 years. If 15 years ago the elder one was twice as old as the younger one. Find their present ages
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The difference between the ages of two sisters is 10 years.
If 15 years ago the elder one was twice as old as the younger one.
Find their present ages
:
Two sisters a & b
"The difference between the ages of two sisters is 10 years."
a - b = 10
or
a = (b+10)
:
"If 15 years ago the elder one was twice as old as the younger one."
a - 15 = 2(b - 15)
a - 15 = 2b - 30
a = 2b - 30 + 15
a = 2b - 15
Replace a with (b+10)
b + 10 = 2b - 15
10 + 15 = 2b - b
25 = b
:
So b is 25, you can find a, Check your solutions in the 2nd statement