__Tank problem__:
What is the rate of flow in the first pipe? If the tank holds
g gallons, then the rate of flow should be g/15 gallons
per minute. So, what is the rate of flow for the other two pipes.

Now use the formula:

Amount = (rate of flow) x (time) to calculate the time using all 3 pipes. Let time = t and amount = g.

__Rectangle to Square problem__: The cuts are not straight cuts. Try thinking about
the symmetry of the problem. After the two cuts are made, the
two pieces are the same size and shape.