csat-suneung 2009 Q16

csat-suneung · South-Korea · csat__math-humanities 4 marks Independent Events
Bag A and Bag B each contain five marbles with the numbers $1,2,3,4,5$ written on them, one number per marble. Chulsu draws one marble from Bag A, and Younghee draws one marble from Bag B. They check the numbers on the two marbles and do not put them back. This process is repeated. What is the probability that the numbers on the two marbles drawn the first time are different, and the numbers on the two marbles drawn the second time are the same? [4 points]
(1) $\frac { 3 } { 20 }$
(2) $\frac { 1 } { 5 }$
(3) $\frac { 1 } { 4 }$
(4) $\frac { 3 } { 10 }$
(5) $\frac { 7 } { 20 }$
Bag A and Bag B each contain five marbles with the numbers $1,2,3,4,5$ written on them, one number per marble. Chulsu draws one marble from Bag A, and Younghee draws one marble from Bag B. They check the numbers on the two marbles and do not put them back. This process is repeated. What is the probability that the numbers on the two marbles drawn the first time are different, and the numbers on the two marbles drawn the second time are the same? [4 points]\\
(1) $\frac { 3 } { 20 }$\\
(2) $\frac { 1 } { 5 }$\\
(3) $\frac { 1 } { 4 }$\\
(4) $\frac { 3 } { 10 }$\\
(5) $\frac { 7 } { 20 }$