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Numerical Ability
Probability
Three dice are rolled. What is the probability that you will get the sum of the numbers as 10?
Read Solution (Total 5)
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- n(s)=6^3=216.
no. of ways to get 10 as sum r
(2,2,6) -> 3!/2!=3.
(2,4,4) -> 3!/2!= 3
(1,3,6) -> 3!=6
(1,4,5) -> 3!=6
(2,3,5) -> 3!=6
(3,3,4) -> 3!/2!=3
Total n(e)=27.
Probability=n(e)/n(s)=27/216=1/8. - 11 years agoHelpfull: Yes(28) No(1)
- 27/216
Let E be the event to get sum as 10
So E= {136,145,154,163,
226,235,244,253,262
316,325,334,343,352,361,
415,424,433,442,451
514,523,532,541
613,622,631}
N(E)= 27
now n(s) = 216. ( here s sample space )
so p(E)= 27/216=1/8 - 11 years agoHelpfull: Yes(2) No(0)
- total sample space=216
total event=27
so probability=27/216 - 11 years agoHelpfull: Yes(0) No(2)
- total sample space=216
total event=27
so probability=27/216 - 11 years agoHelpfull: Yes(0) No(2)
- basically its solving for equation x+y+z=10,
where x,y,z can take any value of 1,2,3,4,5,6;
solving this equation :
think x+y+z =10 like this,
number of ways we can distribute each 1 (10 one's ) by 2 sticks(sticks represent + sign)
e.g. 1 1 1 | 1 1 1 1 | 1 1 1
gap is filled by 2 sticks in this example making a possible permuation as 3+3+2;
1 Gap 1 Gap 1 Gap 1 Gap 1 Gap 1 Gap 1 Gap 1 Gap 1 Gap 1
so we can chose 2 gaps out of 9 gaps in 9C2 ways.
but
1+1+8
1+8+1
8+1+1
1+2+7 (permuate it in 3!=6 ways)
so 3 +9 of them must be subtracted out from 9C2.
9C2-9=27 ways.
probablity= 27/216. - 4 years agoHelpfull: Yes(0) No(0)
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