There are

ways of selecting two of the six blocks at random. The probability that one of them contains an error is

So

has probability mass function

These are the only two cases since there is only one error known to exist in the code; any two blocks of code chosen at random must either contain the error or not.
The expected value of finding an error is then
If it can be assumed that the total number paper and bags is the same for both orders, then:
#bags ordered in the spring=7*(150/3)=350, so the total of both is 150+350=500. A 5:5 ratio means that the wrapping paper and bags were bout in equal quantities. That means 500/2=250 for each.
Answer:
The pair of slacks would be
C. $20.30
Step-by-step explanation: