Algebra
# System of Linear Equations

To keep track of time, an adventurer carries two cylindrical candles of equal heights but different radii. One takes 6 hours and the other takes 9 hours to burn out.

Now, the adventurer lights both candles and goes to sleep. If one candle is twice the height of the other when he wakes up, how much time has he slept?

Two cars get closer by 9m every second while traveling in opposite directions (toward each other). They get closer by 1m every second while traveling in the same direction.

If the speeds of the cars are $X \text{ m/s}$ and $Y \text{ m/s}$, then find $X\times Y$.

In splitting up $1000, a group of three married couples agrees upon the following plan:

The wives receive a total of $396, of which Mary gets $10 more than Diane, and Ellen gets $10 more than Mary.

Bill Brown gets twice as much as his wife, Henry Hobson gets the same as his wife, and John Jones gets 50 percent more than his wife.

What are the full names of the three wives?

Note: Assume that the wives have the same last names as their husbands.