Suppose a jar contains 9 red marbles and 40 blue marbles. If 2 marbles are randomly chosen from the jar at the same time, find the probability that both marbles are red. Round your answer to four decimal places.

0.0306

Step-by-step explanation:

I don't know if there is any significance to both being drawn at the same time. I'm going to say there isn't.

The first draw gives

9/49

Their is no replacement. That's because both marbles are drawn together. The second draw is

8/48

P(both red) = 9/49 * 8 / 48 = 3/98 = 0.03061 which rounds to 0.0306

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb