Sue has 20 biscuits in a tin. there are: 12 plain biscuits 5 chocolate biscuits 3 currant biscuits. sue takes at random two biscuits from the tin. work out the probability that the two biscuits were not the same.

58.43%

Step-by-step explanation:

In this case we have that the probability that they are different is the opposite of the probability that they are the same, therefore, in each case it would be:

P (plain, plain) = (12/20) (11/19)

P (p, p) = 132/380

P (chocolate, chocolate) = (5/20) (4/19) = 20/380

P (ch, ch) = 20/380

P (currant, currant)= (3/20) (2/19) = 6/380

P (c, c) = 6/380

The probability that they are equal is the sum of each:

P (equal) = 132/380 + 20/380 + 6/380

P (equal) = 0.4157

Therefore, the probability that they are different is:

P (different) = 1 - 0.4157

P (different) = 0.5843 = 58.43%

It means that the probability is 58.43%