Anna has a box that contains 4 red marbles and 3 green marbles. All of the marbles are the same size. Without looking inside the box, what is the probability she will draw a red marble from the box, and then,
without replacing the first marble, draw another red marble?
A 1 / 2 B. 2/7 C. 4/7 D. 5/9

5

step-by-step explanation:

the solution is the point

step-by-step explanation:

we have

> equation a

> equation b

adds equation a and equation b

substitute the value of x in equation b to find the value of y

the solution is the point

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.