Latest Infosys Aptitude Question SOLUTION: A can hit a target 6 times in 7 shots. B can hit the target 4 times in 5 shots, C can hit 3 times in 4 shots. What is the chance that the target is damaged by exactly 2 shots? a)18

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A can hit a target 6 times in 7 shots. B can hit the target 4 times in 5 shots, C can hit 3 times in 4 shots. What is the chance that the target is damaged by exactly 2 shots?
a)18/140
b)30/140
c)40/140
d)50/140
e)54/140

Asked In Infosys (12 years ago)

Unsolved Read Solution (5)

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Dr.Dipin Singh  (12 years ago)

I think each person A ,B and C are taking one chance each and we are supposed to find prob of hitting target by exactly two shots out of 3 shots.
so desired combinations are
A...B....C
Hit hit miss
Hit miss hit
Miss hit hit

person A will hit the target six out of seven times, so his hit probability is 6/7, and his miss probability is 1/7.

B's hit probability is 4/5, and his miss probability is 1/5.

C's hit probability is 3/4, and his miss probability is 1/4.

So the probability that the target will be in (Miss hit hit)condition after the shooting = (1/7) * (4/5) * (3/4) = 12/140.

prob of condition (hit miss hit) (6/7) * (1/5) * (3/4) = 18/140.

prob of condition (hit hit miss)= (6/7) * (4/5) * (1/4) = 24/140.

The sum of the three probabilities = prob of hitting target exactly twice 54/140 ........ option e)

Is this solution Helpfull? Yes (25) | No (1)  

Mukesh  (8 years ago)

(6/7)x(4/5)x(1/4)+(6/7)x(1/5)x(3/4)+(1/7)x(4/5)x(3/4) = 54/140

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priyanka priya  (8 years ago)

(6/7*4/7*1/4)+(1/7*4/5*3/4)+(6/7*3/4*1/5) = 54/140

Is this solution Helpfull? Yes (1) | No   

kirti shobhakant mandal  (7 years ago)

the answer is 18/140

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SANGAVI S  (7 years ago)

(ab)/100/(ba)/100=1

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