a coin is tossed until a head appears until it has been tossed three times given that head does not occur on first toss what is tha probabilite that coin is tosse three times?

Question

paki · Answer

hello... and welcome to open study.... 

you know anything about probability....? @marinakhan

anonymous · Answer

yes

paki · Answer

ok, then please tell me the possible outcomes of this coin...?

anonymous · Answer

{HHH HHT HTH THH TTT THT TTH HTT}

anonymous · Answer

Wait, it is only tossed 3 times?

anonymous · Answer

"until a head appears until it has been tossed three times"

Is this an 'or' or and 'and' condition?

anonymous · Answer

I don't understand this question properly  so plz help me to solve it

paki · Answer

possible outcomes will be  H, TH, TTT, and TTH; the favorable outcomes are TTT and TTH....?

anonymous · Answer

how?

paki · Answer

condition Head...

anonymous · Answer

???

anonymous · Answer

if head does not occur on first toss then tail occurs so why the first possibility is H and not T?

anonymous · Answer

helloo?