OK. The population turnover is 24,000 every ten years. So that's 24,000 x 100 in 1000 years, or 2,400,000 individuals born in 1000 years. If the NL mutations amount to 1 per million, then there will be 2.4 mutations.
At least, that's my best guess.
That was my answer.
Son thought it had to do with every 10 years, 120,000 are born so in a thousand years 12,000,000 births would give you a rate of 1.2.
Not really a for credit problem, they just turn in their homework, get credit that they've worked on it and then discuss it.