Depends ENTIRELY on the Breeds, with some influence of age and time of year (average hours of light at your location).
I have 55 birds, mostly hens, and don't see 12 dozen a week, though I get close. If I let a few more age up, and they get "into sync", I'll probably blow past that number. There is a tremendous amount of variation - and if you are going for a rainbow basket, you will be dealing with a lot of mutts who may vary significantly as individuals.
I have birds that lay, consistently, 5 days out of 7. That's 260 eggs a year. I have birds that lay 3 days out of 5. That's 220 eggs a year. and I have birds that lay with I know not what frequency (problem of a large mixed flock whose eggs are all various shades of pale tan to soft brown). But I know I'm good for 18-20 eggs a day, 2-3 of which will be pekin duck eggs (half my Pekins are immature, and half of the remaining are just starting to lay).
Ameraucana are not famed as frequent egg layers. Barnevelders, with their red-brown eggs are not famed as frequent egg layers. Cochins, Langshans, Marans all have unusual egg colors (in that they tend to be towards the extremes of color), none are famed as prodigious layers of eggs.
Now in the medium browns, there are lots of good egg layers like Welsummers, and plenty of sex links lay moderately brown eggs almost daily, while the typical parent stock of those sex links - the RIR, NHR, barred Rock, etc aren't far behind.
Your goal is roughly 7,500 eggs per year. If we assume 220 eggs per hen per year (/HY) on average for your flock, you want 34-35 prime laying hens. If we assume 260 eggs/HY, your target is 29-30 prime laying hens. If many of your hens are at the low end, just 180 eggs a year, now you need over 40.
...and the last two variables?
Time of year. During late summer, early fall, you might blow way past your target - but during late winter early spring when many birds stop or reduce their lay, you might struggle to get 8 dozen a week (or not, since your flock will all be less than a year old come January)
Hen age - Sex links are generally selected for early maturity and egg production. Typically start laying between 16 and 20 weeks, so eggs you hatch this month (or chicks bought as day old pullets) could be laying by mid-late September. Some other breeds might not start laying until mid November, or later - and due to the shortening amount of daylight (see above, multiple mentions) a few may delay start of lay until early Spring.
Essentially, make an educated guess, roll your dice, take your chances. No guarantees.
