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Probability & Statistics
202. What is the probability that a divisor probabilities of failure of the
96
99
of 10 is a multiple of 10 ? machines are given as:
(a) 1/625 (b) 4/625 P = A 0.15, P = B 0.05 and P = 0.1
C
(c) 12/625 (d) 16/625
[GATE-2010 (CS)]
203. The probability that a student knows
the correct answer to a multiple
choice question is 2/3. If the student Assuming, independence of failures
does not know the answer, then the of the machines, the probability that a
student guesses the answer. The given job is successfully processed
probability of the guessed answer (up to the third decimal place) is
being correct is 1/4. Given that the [GATE-2014 (IN-SET1)]
student has answered the question 206. Parcels from sender S receiver R pass
correctly, the conditional probability sequentially through two post-offices.
that the student knows the correct 1
answer is Each post-office has a probability
2 3 5
(a) (b) of losing an incoming parcel,
3 4 independently of all other parcels.
5 8 Given that a parcel is lost, the
(c) (d)
6 9 probability that it was lost by the
[GATE-2013-ME] second post-office is ____
204. An automobile plant contracted to [GATE-2014-EC-SET 4]
buy shock absorbers from two 207. The security system at an IT office is
suppliers X and Y. X supplies 60% composed of 10 computers of which
and Y supplies 40% of the shock exactly four are working. To check
absorbers. All shock absorbers are whether the system is functional, the
subjected to a quality test. The ones officials inspect four of the computers
that pass the quality test are picked at random (without
considered reliable. Of X’s shock replacement). The system is deemed
absorbers, 96% are reliable. Of Y’s functional if at least three of the four
shock absorbers, 72% are reliable. computers inspected are working. Let
The probability that a randomly the probability that the system is
chosen shock absorber, which is deemed functional be denoted by p.
found to be reliable, is made by Y is Then 100p = _________.
(a) 0.288 (b) 0.334 [GATE-2014 (CS-SET2)]
(c) 0.667 (d) 0.720 208. The chance of a student passing an
[GATE-2012] exam is 20%. The chance of student
205. The figure shown the schematic of a passing the exam and getting above
production process with machines A, 90% marks in it is 5%. Given that a
B and C. an input job needs to be student passes the examination, the
preprocessed either by A or by B probability that the student gets above
before it is fed to C, from which the 90% marks is
final finished product comes out. The
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