This just needs some algebra:
(1) y = 4x
(2) y - 5 = 5 (x - 5)
Substituting, distributing, and rearranging:
(3) y = 5 (x - 5) + 5
(4) 4x = 5x - 25 + 5
So:
(5) x = 20
and
(6) y = 80
One way, using XL:
A2: =4 * A1
A3: =5 * (A1 - 5) + 5
A4: =A3 - A2
Choose Tools/Goal Seek. Enter:
Set cell: A4
To value: 0
by changing cell: A1
and click OK.
In article ,
"Beau" wrote:
I want to know how to calculate an unknown number based on facts.
I'm basically trying to perform algebraic equations with excel.
Could someone give me a hand with this theoretical question:
A man, when asked by his niece how old he was, replied, "My age is now four
times yours, but five years ago it was five times yours." How old was he?
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