In this question, we are given:
A = {1, 2, 3, 4, 5} and B = {1, 2, 3, 4, 5, 10}
We choose 4 numbers from each set, and we want P(Sum of A') > P(Sum of B')
If 10 is selected in B', then the smallest possible sum of B' = 10 + 1 + 2 + 3 = 16, but the largest possible sum of A' = 2+3+4+5 = 14.
Thus, if 10 is selected, success is impossible. Hence, B' must exclude 10.
Now for calculating the probability that B' excludes 10 => There are 6C4 = 15 ways to choose 4 numbers from B. To exclude 10, choose 4 from the other 5 - 5C4 = 5.
Therefore, probability of B' excluding 10 = 5/15 = 1/3
Now, compare the possible sums:
Once 10 is excluded, both A' and B' are choosing 4 numbers from: {1,2,3,4,5}
There are exactly 5 possible 4-number selections:
{1,2,3,4} Sum = 10
{1,2,3,5} Sum = 11
{1,2,4,5} Sum = 12
{1,3,4,5} Sum = 13
{2,3,4,5} Sum = 14
So, each sum is one of 10, 11, 12, 13 and 14.
Count when A' has the greatest sum: 5*5 = 25 possible pairs of sum
We need the A' sum to be strictly greater:
If A' = 10 => 0 possibilities
If A' = 11 => B' = 10 -> 1 possibility
If A' = 12 => B' = 10, 11 -> 2 possibilities
If A' = 13 => B' = 10, 11 and 12 -> 3 possibilities
If A' = 14 => B' = 10, 11, 12 and 13 -> 4 possibilities
Total = 0+1+2+3+4 = 10
Thus, P(A' > B' | B' excludes 10) = 10/25 = 2/5
Combining the probabilities as both are necessary: 1/3 * 2/5 = 2/15
Hence, the correct answer is
Option A = 2/15.
Hope this helps!