A number is chosen uniformly at random from among the positive integers less than $10^8$. Given that the sum of the digits of the number is 9, what is the probability that the number is prime

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.

sorry, i can't understand your question. will later if you describe more clearly!

: )

10

step-by-step explanation:

7+3=10

3, 12, 48, 384, 1536, 6144, 24576, 98304

step-by-step explanation:

just keep timing it by 4.