Ladies' Diary/Ratios of Ages of Groom to Bride

Puzzle

A person remarked that upon his wedding day the proportion of his own age to that of his bride was $3$ to $1$,
but $15$ years afterwards the proportion of their ages was $2$ to $1$.
What were their ages upon the day of their marriage?

Solution

The bride was $15$ and the groom was $45$ when they married.

Outrageous.

Proof

Let $x$ and $y$ be the ages of the bride and groom at their marriage respectively.

We have:

 $\ds 3 x$ $=$ $\ds y$ $\ds 2 \paren {x + 15}$ $=$ $\ds y + 15$ $\ds \leadsto \ \$ $\ds 2 x + 30$ $=$ $\ds 3 x + 15$ $\ds \leadsto \ \$ $\ds x$ $=$ $\ds 15$ $\ds \leadsto \ \$ $\ds y$ $=$ $\ds 45$

$\blacksquare$