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If the head of a coin is worth 1 point and the tail is worth 2 points,
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31 Mar 2022, 02:00
31 Mar 2022, 02:00
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Question Stats:
90% (01:21) correct
10% (00:52) wrong based on 10 sessions
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If the head of a coin is worth 1 point and the tail is worth 2 points, what is the probability that the sum of the results of 4 tosses is at least 5 points?
(A) 3/8
(B) 1/2
(C) 3/4
(D) 7/8
(E) 15/16
(A) 3/8
(B) 1/2
(C) 3/4
(D) 7/8
(E) 15/16
Part of the project: Skill Builder Project for a Q170
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GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
Re: If the head of a coin is worth 1 point and the tail is worth 2 points,
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10 Apr 2022, 08:33
10 Apr 2022, 08:33
2
first let's see what are the point that we get
1. All head = 1+1+1+1 =4
2.one tail and 3 head = 2+1+1+1 =5
3.two tails and = 2+2+1+1=6
we can see that except all head even if one tail comes in it gives 5 or higher...so we should use 1- unfavourable ..to find the probability
so getting 4 points (= all heads) = 1/16
required probability =1-1/16 = 15/16
1. All head = 1+1+1+1 =4
2.one tail and 3 head = 2+1+1+1 =5
3.two tails and = 2+2+1+1=6
we can see that except all head even if one tail comes in it gives 5 or higher...so we should use 1- unfavourable ..to find the probability
so getting 4 points (= all heads) = 1/16
required probability =1-1/16 = 15/16
Re: If the head of a coin is worth 1 point and the tail is worth 2 points,
[#permalink]
10 Apr 2022, 15:33
10 Apr 2022, 15:33
1
Possible outcomes:
4 head: 1+1+1+1 = 4
3 head and 1 tail = 1+1+1+2 = 5
Adding any tail from now, the sum is greater than 5.
Therefore, the target outcome is every outcome except 4 heads and that means 1 - 1/16 = 15/16.
Where does 1/16 come from?
It´s the probability to get 4 head: 1/2 x 1/2 x 1/2 x 1/2
4 head: 1+1+1+1 = 4
3 head and 1 tail = 1+1+1+2 = 5
Adding any tail from now, the sum is greater than 5.
Therefore, the target outcome is every outcome except 4 heads and that means 1 - 1/16 = 15/16.
Where does 1/16 come from?
It´s the probability to get 4 head: 1/2 x 1/2 x 1/2 x 1/2
