pr.probability – Find the probability that: (b) exactly 3 devices broke down if it is known that at least 1 device broke down

There are 10 devices. Every device independently breaks down with probability 0.15. Find the probability that:
(b) exactly 3 devices broke down if it is known that at least 1 device broke down
I just forgot, there was a formula for determining if there is a known condition or something, also I forgot the book’s name that studied this probability. Could you please tell he formulas?