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06 May 2019, 01:22
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Three students, Mark, Peter, and Wanda, are all working on the same math problem. If their individual probabilities of success are 1/4, 2/5, and 3/8, respectively, then what is the probability that at least one of the students will get the problem correct?
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
Updated on: 07 May 2019, 01:30
Originally posted by Archit3110 on 06 May 2019, 03:48.
Last edited by Archit3110 on 07 May 2019, 01:30, edited 1 time in total.
Last edited by Archit3110 on 07 May 2019, 01:30, edited 1 time in total.
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Bunuel
Three students, Mark, Peter, and Wanda, are all working on the same math problem. If their individual probabilities of success are 1/4, 2/5, and 3/8, respectively, then what is the probability that at least one of the students will get the problem correct?
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
CASE 1
mark right ; 1/4 ; wrong 3/4
peter right ; 2/5 ; wrong ; 3/5
wanda right; 3/8 ; wrong 5/8
so
we get following cases ; 1/4* 3/5*5/8 + 2/5*3/4*5/8+ 3/4*3/5*3/8+1/4*2/5*5/8+1/4*3/8*3/5+2/5*3/8*3/4+1/4*2/5*3/8
; 115/160 ; 23 /32
IMO C
CASE 2
else all wrong cases; 3/4*3/5*5/8 = 9/32
1- wrong cases ; 1-9/32 ; 23/32
IMO C
06 May 2019, 04:05
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Three students, Mark, Peter, and Wanda, are all working on the same math problem. If their individual probabilities of success are 1/4, 2/5, and 3/8, respectively, then what is the probability that at least one of the students will get the problem correct?
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
Probability that no student will get the answer correct will be 3/4*3/5*5/8 = 9/32
Probability that at least one student get the answer correct will be 1- 9/32= 23/32
Choice C is correct.
Thanks & Regards
Posted from my mobile device
A. 3/80
B. 9/32
C. 23/32
D. 77/80
E. 39/40
Probability that no student will get the answer correct will be 3/4*3/5*5/8 = 9/32
Probability that at least one student get the answer correct will be 1- 9/32= 23/32
Choice C is correct.
Thanks & Regards
Posted from my mobile device
