Verified answer

1.in a group of 200 college students 138 are enrolled in a course in psychology 115 are enrolled in a course in sociology and 91 are enrolled in both how many of these students are not enrolled in either course?solution:

the number of which in either course : 138+115-91=162

the number of students are not enrolled in either coursev:200-162= 38

2.a bin contains 100 balls of which 25 are red 40 are white and 35 are black if two balls are selected from the bin without replacement what is the probability that one will be red and one will be white?

solution:

1. the first case is : first one is red and second one is white

then the probability is 25/100 x 40/99= 10/99

2. the second case is : first one is white and second one is red

then the probability is 40/100 x 25/99= 10/99

then the probability that one will be red and one will be white is

10/99+ 10/99 =20/99