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Re: CR necessary and sufficient [#permalink]
25 Nov 2004, 12:32
X is necessary for Y to happen
Z is sufficient for Y to happen
Can we conclude 1-- If Y happens X happened 2-- IF Y did not happen X did not happen 3-- If Y happened Z happened 4-- If Y did not happen, Z did not happen
Could someone explain ?
I will pick 1 too. But I have a problem with the question stem... If Z is sufficient for Y to happen it implies that just Z is enough for Y to happen then how can X be necessary for Y to happen?
Well Z maybe enough, but X is NECESSARY. Suppose, I can leave my home when my mom returns, but i need to tell her something very imp. before leaving. So it is NECESSARY that she come \s back before I leave. My dad might come back in the middle (which is sufficient for me to leave), but it is not NECESSARY. So I cant leave even when he comes back.. am I making my point clear? _________________