10 kids are randomly grouped into an A team with five kids and a B team with five kids. Each grouping is equally likely. There are three kids in the group, Alex and his two best friends Jose and Carl. What is the probability that Alex ends up on the same team with at least one of his two best friends?

The probability that Alex ends up on the same team with at least one of his two best friends = 0.7222

Step-by-step explanation:

Number of ways to select r items from n, nCr = n!/(r! x (n-r)!)

P(Alex ends up on the same team with at least one of his two best friends) = 1 - P(Alex ends upon a team with none of his two best friends)

= 1 - P(4 other people in Alex's group are chosen from the 7 other kids)

= 1 - Number of ways to pick 4 kids from 7 / Number of ways to pick 4 kids from 9

= 1 - 7C4 / 9C4 = 1 - 35/126

= 0.7222

c

c

c

c

c

c

c

cc

c

step-by-step explanation:

the simplified form is

step-by-step explanation:

we want to simplify the expression,

let us change the middle bar to a normal division sign to obtain,

we multiply the first fraction by the reciprocal of the second fraction to obtain,

we factor to obtain,

we cancel the common factors to get,

we simplify to get,

the correct answer is b