M7MBA wrote: ↑

Wed Jun 24, 2020 6:27 am

Jessica's laundry basket contains 15 different pairs of socks. If she reaches into the basket and pulls two socks at random, what is the probability that she pulls out a matching pair?

A. 1/900
B. 1/870
C. 1/210
D. 1/29
E. 1/28

[spoiler]OA=D[/spoiler]

Source: Veritas Prep

Given that there are 15 different pairs of socks, there are 15*2 = 30 different socks

After randomly picking one sock, we are left with 29 socks; out of these 29, only one would be paired with the already-picked sock. So the required probability = 1/29.

Correct answer: D

Hope this helps!

-Jay
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M7MBA wrote: ↑

Wed Jun 24, 2020 6:27 am

Jessica's laundry basket contains 15 different pairs of socks. If she reaches into the basket and pulls two socks at random, what is the probability that she pulls out a matching pair?

A. 1/900
B. 1/870
C. 1/210
D. 1/29
E. 1/28

[spoiler]OA=D[/spoiler]

Solution:

The first sock can be any sock. For the second sock, there is only 1 out of the remaining 29 socks that can match the first sock. Therefore, the probability of pulling out two socks that are a matching pair is 1/29.

Answer: D