Amanda and Mofor are selling wrapping paper for a school fundraiser. Customers can buy rolls of plain wrapping paper and rolls of holiday wrapping paper. Amanda sold 13 rolls of plain wrapping paper and 12 rolls of holiday wrapping paper for a total of $208. Mofor sold 4 rolls of plain wrapping paper and 3 rolls of holiday wrapping paper for a total of $55. Find the cost of one roll of plain wrapping paper and one roll of holiday wrapping paper. Write two separate equations and find the cost of one roll of plain wrapping paper and one roll of holiday wrapping paper.

(a) 0.24

(b) 0.76

Step-by-step explanation:

We are given that let Y be the number of homes with a dust mite level that exceeds 2 mg/g. The probability distribution for Y=y is shown below ;

     y                 P(y)

     0                 0.09

     1                  0.30

     2                 0.37

     3                 0.20

    4                  0.04

(a) Probability that three or four of the homes in the sample have a dust mite level that exceeds 2 µg/g = P(y = 3) + P(y = 4)

                                           = 0.20 + 0.04 = 0.24 .

(b) Probability that fewer than three homes in the sample have a dust mite level that exceeds 2 µg/g = P(y = 0) + P(y = 1) + P(y = 2)

                                           = 0.09 + 0.30 + 0.37 = 0.76 .