A bag contains 4 yellow chips, 6 black chips, and 1 green chip. You pull two chips without replacing them. Find the following probabilities. P (yellow and black)

90/121. There are 11 chips total. Once you pull a yellow one, there are 10 out of 11 left. Then you pull a black one from there, which leaves you with 9 out of 11 chips. Then you multiply 10 out of 11 by 9 out of 11 to get your probability.