self Maths Puzzle

counters marked 1,2,3 are placed in a bag and one of them is withdrawn and replaced.the operation being repeated three times,what is the chance of obtaining a total of 6 in these three operations.

Read Solution (Total 2)

total(1,2,3)=n^r (repetition is allowed)
=3^3=>27
total=6
=>(1+2+3)'s cases=3!=6
=>(2+2+2)'s cases=1

so,answer=(6+1)/27=7/27
10 years agoHelpfull: Yes(10) No(0)

ans is 2/27
10 years agoHelpfull: Yes(0) No(5)

self Other Question

out of a pack of 52 cards one is lost,from the remainder of the pack,two cards are drawn and found to be spades.find the chance that the missing card is a spade. in a bag there are 10 black,8 white,and 5 red balls.three balla are chosen at random and one is found to be black.the probability the the rest two are white is?