Hello, spaarky!

A challenging problem . . . I haven't solved it yet.

$\displaystyle \text{There are 68 liters of water in tank }X\text{ and tank }Y.$

$\displaystyle \text{The heights of the water in both tanks are equal.}$

$\displaystyle \text{Tank }Y\text{ is 40\% full of water.}$

$\displaystyle \text{When the water from tank }Y\text{ is poured into tank }X,$

. . $\displaystyle \text{4 liters overflowed.}$

$\displaystyle \text{(A) Find the height of the water in tank }X\text{ at first.}$

$\displaystyle \text{(B) Find the capacity of tank }Y.$

This how I envision the two tanks and the water.

Code:

Tank X Tank Y
* *
| |
| | * *
| | | |
* - - - * * - - - - - *
|:::::::| |:::::::::::|
h|:::A:::| h|:::::B:::::|
|:::::::| |:::::::::::|
*-------* *-----------*

There are $\displaystyle A$ liters of water in tank $\displaystyle X.$

There are $\displaystyle B$ liters of water in tank $\displaystyle Y.$

We know that: .$\displaystyle A + B \:=\:68$

We see that: .$\displaystyle A+B \,=\,68$ is 4 more than the capacity of tank $\displaystyle X.$

. . Hence, the capacity of tank $\displaystyle X$ is 64 liters.

We know that $\displaystyle \,B$ is 40% of the capacity of tank $\displaystyle Y.$

I need at least one more equation . . . Where is it?