Suggest one way of sizing the transistors of the logic

[bubothedog]

Homework Statement

Suggest one way of sizing the transistors of the logic circuit such that its worst case
tpHL equals the tpHL of an inverter with a sizing of (W/L)min.

Homework Equations

I think the only equation is the (W/L) itself.

The Attempt at a Solution

I have actually done the front part of the question and I got the worst case ratio to be 3. But I am not too sure about the theory part to suggest a way. Anyone help?

 

[bubothedog]

anyone?

 

[mfb]

I probably can't help with the question, but I wonder how you got "3" without any numbers given in the problem statement.