About a month ago, my high school had its first math team competition. In one of the events (Fr/So 8-person), the following question was asked:
"All ages in this problem are in whole number of years. Tom is now 3 times as old as Kay was when Tom was 4 times as old as Kay had been when Kay was 1/2 as old as Kay is now. If the sum of their present ages is 26 years, find the number of years in Tom's age now.
What would be a strategy that I could use to simplify it down into easier to understand equations, and then to solve it?
I think the main problem lies in this sentence:
Let Tom be $X$ years old and Kay be $Y$ years old. Break down from back to front:
when Kay was 1/2 as old as Kay is now
-> when Kay was $\frac Y2$ years old
-> $\frac Y2$ years ago.
when Tom was 4 times as old as Kay had been when Kay was 1/2 as old as Kay is now.
-> when Tom was 4 times as old as Kay had been $\frac Y2$ years ago.
-> when Tom was $4 \cdot \frac Y2$ years old
-> $X-2Y$ years ago
Tom is now 3 times as old as Kay was when Tom was 4 times as old as Kay had been when Kay was 1/2 as old as Kay is now.
-> Tom is now 3 times as old as Kay was $X-2Y$ years ago
-> $X = 3\cdot[Y-(X-2Y)]$
-> $4X=9Y$