Trouble with urn question

Question

The urn holds 300 blue & 700 green balls. Select 10 balls with replacement,

there are a total of 1k balls. This is a combination question I'm sure, but I am getting a big number when trying to solve this by Expressing the answers as fractions with exponents

Maybe my math is way off,

What is the probability all ten balls are blue? (300C10/ 1000c10) is this how I would do the math?

What is the probability at least one ball is green. Not sure how to do this one.

Answer 1

.3^10 = about 5.905 x 10^-6 = 0.0000059 =about 0.0006% chance of all blue= very unlikely

Pr(at least one green)= 100% minus chance of all blue = about 99.9994% = virtually certain