"Cralo" sea food restaurant is famous for fresh crab and lobsters. The

Question

"Cralo" sea food restaurant is famous for fresh crab and lobsters. The restaurant has two tanks. The customers has to choose their dinner from the tanks. Tank A has 28 lobsters and 12 crabs. Tank B has 12 lobsters and 28 crabs. For Susan its a nasty experience to see her dinner alive, so she closes her eyes and randomly points at the lobsters or crabs. If she points at a lobster what is the probability that it is from tank A ?

(A) 7/10
(B) 1/2
(C) 7/20
(D) 1/4
(E) 7/40

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Official Answer

A

(A) 7/10
(B) 1/2
(C) 7/20
(D) 1/4
(E) 7/40

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TarunKumar1234 · Answer

Given, Tank A: 28L + 12C and Tank B: 12L+ 28C So, Total L = 28+12 = 40 P(E) = 28/40= 7/10, So, I think A.

naveeng15 · Answer

its bit a tricky question ,

since she has already chosen "LOBSTER"

P(choosing Lobster from Tank A) = 28/40 = 14/20 = 7/10

Oandrla · Answer

Total Outcome = probability of selecting a lobster from either A or B

Probability to select Lobster from A =28/40*1/2= 7/20
Probability to select Lobster from B = 12/40*1/2= 3/20

Total Outcome = 17/20+3/20= 10/20

Favourable outcome = Probability to select Lobster from A =28/40*1/2= 7/20

= 7/20 / 10/20 = 7/10

In this case the likelyhood of picking a tank is 50% or 1/2

ZIX · Answer

The concept here is that probability gets updated with new information. It's the best approximation we can make with the available information.

farmania · Answer

Pls guide where am I going wrong.

I think the answer should be 7/20, but the correct answer is 7/10.

My reasoning - 
Probability of choosing a tank = 1/2
Probability of choosing lobster in tankA = 28/40 = 7/10

Total total probability of choosing lobster from tankA = 1/2 * 7/10 = 7/20

ZIX · Answer

We already know that she chose a lobster, so we have to ignore the probability of her choosing crabs. Now, there are total 40 lobsters and out of these 28 are in Tank A, so the probability that she chose a lobster from Tank A is  \frac{28}{40} = \frac{7}{10} .

Denial234 · Answer

We are tasked with finding the probability that a lobster pointed at by Susan is from Tank A, given that she points at a lobster.

Step 1: Total lobsters and crabs in each tank
Tank A: 28 lobsters and 12 crabs.
Total in Tank A = (28 + 12 = 40).
Tank B: 12 lobsters and 28 crabs.
Total in Tank B = (12 + 28 = 40).
Step 2: Total lobsters in both tanks
Total lobsters = (28 + 12 = 40).

Step 3: Probability of pointing at a lobster
The probability of pointing at a lobster from Tank A is proportional to the number of lobsters in Tank A divided by the total lobsters:

Step 4: Final probability calculation
The probability simplifies to:

Final Answer:
(A) ( \frac{7}{10} ).

"Cralo" sea food restaurant is famous for fresh crab and lobsters. The

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"Cralo" sea food restaurant is famous for fresh crab and lobsters. The

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