Clases GMATHome > GMAT Focus Edition Data Insight QUESTION > Data Sufficiency > Probability > A pack of 12 cards contains either red or black cards. What is the (...)
A pack of 12 cards contains either red or black cards. What is the probability that a card chosen at random will be a red card?
Dificultad: Nivel Sub-600, Probabilidad, Suficiencia de Datos (DS)
Monday 25 July 2022, by
A pack of 12 cards contains either red or black cards. What is the probability that a card chosen at random will be a red card?
(1) The pack has 6 more red cards than black cards
(2) The pack has 3 red cards for every black card
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EXPLANATION:
SO B+R=12, and we have to find the value of R12R12 or 1−B121−B12
(1) The pack has 6 more red cards than black cards.
Thus, R=B+6, but we know B+R=12 => B+B+6=12.....B=3, and so R=9.
Probability = 9/12=3/4
Suff
(2) The pack has 3 red cards for every black card
Ratio R:B=3:1, R:(B+R)=R:(T)=3:(3+1)=3:4
So probability = 3/4
Suff
D