Solve classic age problems: in how many years (or how many years ago) will a parent be k times as old as a child. Enter your values; the result updates as you type, with the method shown below.
Formula
a + x = k(b + x) → x = (a − kb) / (k − 1)
Worked example
Parent 40, child 10, twice as old: in 20 years.
Frequently asked questions
How is it set up?
Parent + x = k × (child + x).
Negative answer?
It means it happened in the past.
Other problems?
The same method works for any two people.
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Results are estimates for information only. Check important figures with a professional.