## Goldman Sachs Interview Question for Interns

• 0

Country: United States
Interview Type: Written Test

Comment hidden because of low score. Click to expand.
8
of 8 vote

Prob.(successful first launch) = 0.8
T(successful first launch) = K - C

Prob.(successful second launch) = (0.2)(0.8)
T(successful second launch) = K+(K/3)-C

Prob.(successful third launch) = (0.2)^2(0.8)
T(successful second launch) = K+(2K/3)-C

Prob.(successful fourth launch) = (0.2)^3(0.8)
T(successful second launch) = K+(3K/3)-C

Prob.(successful fifth launch) = (0.2)^4(0.8)
T(successful second launch) = K+(4K/3)-C

Prob.(unsuccessful experiment) = (0.2)^5
T(successful second launch) = K+(4K/3)

This is the probability distribution of T:

Prob.(T = K - C) = 0.8
Prob.(T = 4K/3 - C) = 0.16
Prob.(T = 5K/3 - C) = 0.032
Prob.(T = 6K/3 - C) = 0.0064
Prob.(T = 7K/3 - C) = 0.00128
Prob.(T = 7K/3) = 0.00032

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-1
of 1 vote

why K-C?why n't K+C?
bco'z there's is additional gain of C dollars.

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0

T is the cost, losses must be added and gains must be subtracted from cost. So we add K, K/3 and subtract C!!

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0
of 0 vote

Correct. But it will extend to infinity. So you have to take next trial into account. Also all p's should add to 1

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0
of 0 vote

(.8)(K-C)(.2)^(n-1)
here n is the Nth attempt to launch

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-1
of 1 vote

``E(T) = sum{(k - k / 3 * (i - 1) - C) * p^i * (1-p) ^ (i - 1), i = 1, 2, 3, 4} + (k - k * 4 / 3 - 0) * (1 - p)^5``

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