A Coder and a Half

If a coder and a half write a module and a half in a day and a half, how many modules can 6 coders write in 7 days?

Solution

We know that 1½ coders write 1½ modules in 1½ days.
So 3 coders write 3 modules in 1½ days.
So 6 coders write 6 modules in 1½ days.
So 6 coders write 12 modules in 3 days.
So 6 coders write 24 modules in 6 days.
So 6 coders write 28 modules in 7 days.

The answer is 28 modules.