VeritasPrepKarishma wrote:
bagdbmba wrote:
x, y and z are all unique numbers. If x is chosen randomly from the set {7, 8, 9, 10, 11} and y and z are chosen randomly from the set {20, 21, 22, 23}, what is the Probability that x and y are prime and z is not ?
A. 1/5
B. 3/20
C. 13/20
D. 3/10
E. 1/10
A. 1/5
B. 3/20
C. 13/20
D. 3/10
E. 1/10
x from {7, 8, 9, 10, 11} - there are 2 primes here 7 and 11. Probability that x is prime is 2/5.
y and z from {20, 21, 22, 23} - there is only one prime number here 23. Probability that y is prime is 1/4.
Now you are left with
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