If Jessica rolls a die, what is the probability of getting

Question

If Jessica rolls a die, what is the probability of getting at least a "3"?

Answer to this question is 2/3

but i think it should be 1/6

pls suggest whether i am right or wrong

Bunuel · Answer

Favorable event would be if she gets 3, 4, 5, or 6 (at least 3), so four outcomes out of 6: P= favorable/total=4/6=2/3.

Hope it's clear.

magicmanisha · Answer

Atleat 3 means 3 or more then 3 so outcome will be 3 4 5 6

probability of getting 3 is 1/6 so getting atleast 3 will be 1/6*1/6*1/6*1/6

sanjoo · Answer

I have solved in this way....

probabilty of geting atleast 3..

suppose probability of geting 1 and 2..is ..1/6+1/6..2/6=1/3..

so probability of geting atleast 3 is...1-probability of geting 1 and 2..we l get probabilty of geting atleast 3..rite?

so 1-1/3=2/3..

magicmanisha · Answer

yes this approach is also rit

The probability of each outcome is 1/6. The probability of getting at least a "3" is:

1/6+1/6+ 1/6 +1/6 = 2/3
or what you mentioned

probability of not getting atleast 3

1- (1/6 + 1/6) = 2/3

both methods are fine

yamshi06 · Answer

i approached like this ,
not getting a 3=5/6

atleast=1-5\6
 = 1/6

pls explain what is wrong in the approach??

GMATinsight · Answer

Probability = Favorable Outcomes / Total Outcomes A Die has 6 faces numbered from 1 through 6 i.e. Total Out comes = 6 Favorable outcomes = Numbers atleast 3 = numbers greater than or equal to 3 i.e. {3, 4, 5, 6} = 4 i.e. Probability = 4/6 = 2/3 ALTERNATIVELY Probability = 1 -(Unfavorable Outcomes / Total Outcomes Unfavorable outcomes = Numbers less than 3 = i.e. {1, 2} = 2 i.e. Probability = 1 -(2/6) = 1-(1/3) = 2/3 I hope it clears your doubt!

GMATinsight · Answer

Please Note "If you subtract the probability of NOT getting 3 from 1 then you will get Probability of getting 3"

whereas the question demand the probability of getting   ATLEAST  3

yamshi06 · Answer

we mainly do like dis,
P(at least one success) = 1 – P(no success)

i missing something in this concept plsd explain??

GMATinsight · Answer

You are getting it Right in this context Yashmi

P(at least one success) = 1 – P(no success) is CORRECT

But Probability of buying atleast 2 apples will NOT be same as (1-probability of buying NO apple)

You must Understand that  Probability of buying atleast 2 apples will be equal to (1-probability of NOT buying 2 or more apple)

BrushMyQuant · Answer

Given that Jessica rolls a die and We need to find what is the probability of getting at least a "3"?

As we are rolling one dice => Number of cases =  6^1  = 6

At least a 3 means 3 or more than 3
=> Possible cases are 3, 4, 5, 6 => 4 cases

=> P(Getting at least a 3) =  \frac{4}{6}  =  \frac{2}{3}

So,  Answer will be  \frac{2}{3}  
Hope it helps!

Playlist on Solved Problems on Probability  here

Watch the following video to MASTER Dice Rolling Probability Problems

https://www.youtube.com/watch?v=5PVZYQXet18

If Jessica rolls a die, what is the probability of getting

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