Xander spends most of his time with his 10 closest friends. He has known 4 of his 10 friends since kindergarten. If he is going to see a movie tonight with 3 of his 10 closest friends, what is the probability that the first 2 of the friends to show up to the movie are friends he has known since kindergarten but the third is not?
StartFraction 1 over 30 EndFraction
StartFraction 9 over 125 EndFraction
StartFraction 12 over 125 EndFraction
StartFraction 1 over 10 EndFraction

B

Step-by-step explanation:

D

Step-by-step explanation:

518,400

step-by-step explanation:

the area is multiplying all the given measurements together.

40 * 18 * 30 * 24 = 518,400

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1