probability -2

Q.1
IF 3 FAIR DICES ARE THROWN TOGETHER ,THE PROBABILITY THAT THE SUM OF THE NUMBERS APPEARING ON THE DICE IS K ,WHERE3<=K<=8

Q.2
THE PROBABILITY THAT A RADAR WILL DETECT AN OBJECT IN ONE CYCLE IS P . THEN THE PROBABILITY THAT THE OBJECT WILL BE DETECTED IN N CYCLES IS??

16 Answers

1
Aditya ·

2. it will be the same as they r independent events
i hav gone mad!

1
pavanmalhra ·

NO IT IS NOT SAME

62
Lokesh Verma ·

Q 1)

a+b+c <=8

1+x+1+y+1+z<=8

x+y+z<=5

x, y , z can take values form 0 to 5

so coeff of powers less thanequal to 5 in

(1+x+x2....x5)3

If you are afraid of this method.. take cases for x...

62
Lokesh Verma ·

1-(1-p)n

In this one.. the answer is the explanation too!!

think carefully

1
pavanmalhra ·

ADITYA UR BOTH ANS.... R INCORRECT

1
vector ·

q2 1-(1-p)n

1
pavanmalhra ·

U R RIGHT BHAIYA BUT ANY ALTERNATE METHOD FOR 1

1
vector ·

(1-p)n-1*pbut it s for nth case

1
pavanmalhra ·

RICHA UR FIRST ANS WAS CORRECT

1
vector ·

@pavan method suggested by nishant bhaiya is shortest

62
Lokesh Verma ·

a+b+c <=8

1+x+1+y+1+z<=8

x+y+z<=5

x, y , z can take values form 0 to 5

case x=0
y+z<=5: no of ways is

y=0, then z can take 6 values
y=1, then z can take 5 values
y=2, then z can take 4 values
y=3, then z can take 3 values
y=4, then z can take 2 values
y=5, then z can take 1 values

hence 21 ways,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

case x=1
y+z<=4: no of ways is

y=0, then z can take 5 values
y=1, then z can take 4 values
y=2, then z can take 3 values
y=3, then z can take 2 values
y=4, then z can take 1 values

hence 15 ways,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
similarly 10, 6, 3, 2, 1 ways

hence total no of ways is

21+15+10+6+3+2+1= 58 ways..

see if i have made any calculatin mistake

1
vector ·

however can also do by beggar method

62
Lokesh Verma ·

what is the beggar method richa?

I never heard :(

1
pavanmalhra ·

yaa wats this beggar method

1
pavanmalhra ·

ans for 1 is (k-1)(k-2)/432
how?

62
Lokesh Verma ·

That i guess is the

so coeff of powers less thanequal to k-3 in

(1+x+x2....x5)3

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