Bunuel
There are six cards with numbers 2, 4, 5, 5, 5, and 6 on them. If two cards are randomly selected without replacement, what is the probability that the absolute difference between the numbers on these cards is at most 3?
A. \(\frac{8}{15}\)
B. \(\frac{9}{15}\)
C. \(\frac{10}{15}\)
D. \(\frac{12}{15}\)
E. \(\frac{14}{15}\)
Always remember in questions like these where language says “ at least or a most “ take a pause and remind yourself of this:-
P(success)=1- P(failure)
Here, the only way to "fail" (absolute difference > 3) is to draw the pair {2, 6}. The difference is 6 - 2 = 4.
Scenario A: Draw the 2 first, then the 6
· Draw 1: Probability of drawing a 2 = 1/6 (There is one '2' out of six cards).
· Draw 2: Probability of drawing a 6 = 1/5 (One card is gone, so 5 remain. There is one '6' left).
· Probability of Scenario A: 1/6 * 1/5 =1/30
Scenario B: Draw the 6 first, then the 2
· Draw 1: Probability of drawing a 6 = 1/6 (There is one '6' out of six cards).
· Draw 2: Probability of drawing a 2 = 1/5 (One card is gone, so 5 remain. There is one '2' left).
· Probability of Scenario B: 1/6* 1/5 =1/30
Total Probability of Failure:
Add the two scenarios together:
P(failure) = 1/30 + 1/30 =1/15Now P(success)= 1-1/15 =
14/15Answer option(E)