Elitmus
Exam
Numerical Ability
Probability
ram draws a card randomly among card 1-23 and keep it back.then sam draws a card among those.wht is the prob than sam has drawn a card greatr than ram
Read Solution (Total 3)
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- Sum of probability of drowing a card greater than drawn by ram is (22/23)+(21/23)+.....(1/23)=253/23
but probability for choosing 1 card out of 23 is 1/23
therefore total probability is (253/23)*(1/23)=(11/23)-ans - 9 years agoHelpfull: Yes(19) No(1)
- 253/529
22+21+20+........1=253
ans is 253/23*23 - 9 years agoHelpfull: Yes(8) No(2)
- ram can draw 1 or 2 or 3 or 4......or 23 => p(ram draws 1 card)=1/23
now for shayam can have choices to draw card greater than ram
if ram draws card 1 then shayam has 22 choices so p(E)=1/23*22/23
" " " " 2 " " " 21 " so p(E)=1/23*21/23
so on........
finally when ram draws card 22 then shayam has 1 choice so p(E)=1/23*1/23
so total probability will be sum of all individual events
i.e p(E)=1/23(22/23+21/23+......+1/23)
=>1/23^2(22+21+20+.....1)
=>1/23^2*((22*(22+1)/2)
=>11/23 ans - 7 years agoHelpfull: Yes(0) No(0)
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