Probability Question:

Question

anonymous · Answer

Two identical biased coins are tossed together, and the outcome is recorded. After a large number of trials it is observed that the probability that both coins land showing tails is 0.49. 

What is the probability that both coins land showing heads?

anonymous · Answer

2/4 or 1/2

anonymous · Answer

not that easy (:

anonymous · Answer

@ParthKohli can try :p

anonymous · Answer

do you know the answer @Omniscience

anonymous · Answer

Obv.

parthkohli · Answer

Experimental probability. I see.

anonymous · Answer

Try it (:

anonymous · Answer

why you are asking then @Omniscience

parthkohli · Answer

An approach to this question is P(Heads) = 1 - P(Tails)

anonymous · Answer

Yes, That was what I thought but then that is not the first step.

parthkohli · Answer

P(Heads) = 1 - 0.49

anonymous · Answer

lol, i did the same thing but it is not right.

parthkohli · Answer

Is this experimental or theoretical probability?

parthkohli · Answer

I go for experimental, as it says 'biased'

anonymous · Answer

lol, simple probability; very easy infact (:

parthkohli · Answer

Is it somewhat like this? P(Coin will show a tails in one toss) = $\sqrt{0.49}$?

anonymous · Answer

Very close.

parthkohli · Answer

Glad to hear that. Will the first step show the computation of the probability that the coin will show a 'tails' in one toss?

anonymous · Answer

Well, show the probability of throwing heads first.

parthkohli · Answer

1/2 is theoretical.
1 - 0.49 is experimental.

parthkohli · Answer

Well no...
1 - sqrt0.49

anonymous · Answer

Correct, which is the probability of throwing heads.

anonymous · Answer

Then what is the probabilty that both coins land showing heads?

anonymous · Answer

Wait 1-sqrt0.49; was the probability of head.

anonymous · Answer

one head*

parthkohli · Answer

(1 - sqrt0.49)^2

parthkohli · Answer

$\Rightarrow 1^2 - 2(\sqrt{0.49})(1) + 0.49$

anonymous · Answer

lol what

parthkohli · Answer

$\Rightarrow 1.49 - 2\sqrt{0.49} $?

anonymous · Answer

you are over thinking.

parthkohli · Answer

Omni, that is the identity lol
$(a - b)^2 = a^2 - 2ab + b^2$

parthkohli · Answer

Idk... what else can I do here lol

anonymous · Answer

Don't overcomplicate the question!!

anonymous · Answer

Well, you got it right first; but you over complicated it. 
The answer is $0.09$

parthkohli · Answer

But wait, that is the probability of a head in one toss.

anonymous · Answer

No that is the probability of two heads. Since once head is $0.3$

parthkohli · Answer

Yep

anonymous · Answer

Do you get it?

parthkohli · Answer

Yeah. 
0.3 * 0.3

anonymous · Answer

yes; yaay! ^_^

parthkohli · Answer

lol