Answer:
a. (10/40) * (9/39)
Explanation:
Since, the total number of white box = 10,
Red box = 10,
Green box = 10,
And, Blue box = 10,
Thus, the total number of boxes = 10 + 10 + 10 + 10 = 40
The probability of receiving white box by first winner = White box / Total box = 10/40
Since, the replacing is not allowed ( Because, here boxes are allotted )
Thus, the remaining white box = 10 - 1 = 9,
And, the remaining total boxes = 40 - 1 = 39,
Thus, the probability of receiving white box by second winner = Remaining white box / Remaining total box = 9/39
Hence, the probability of the first winner receiving a white box and the second winner also receiving a box of the same color = 10/40 * 9/39
Which is required expression.