A doctor must see six patients example

[yankees322]

Example:
A doctor must see six patients- C, D, E, F, G and H- one after another, not necessarily in that order. The patients must be seen according to the following conditions:

E is seen exactly three patients after C.
D is seem immediately before F is seen.

When I set up this problem I did the following:

C _ _ _ E (with a block around them) However the correct setup is C _ _ E (with a block around them) Why is the correct format? When it says " E is seen exactly three patients AFTER C...?
I would appreciate it if you could clear this up for me. Thank you

[Dave Killoran]

Hi Yankees,

Thanks for the question. The block you've drawn represents three spaces between C and E.

To see why the block is drawn as is, first look back at pages 18 and 19 of the book. Then consider the placement of C and E. For example, let's just imagine that C is the first patient seen. So, C = 1. If E is seen three patients after C, wouldn't E be 4th (E = 4)? Yes, it would. That would translate to a C __ __ E block (or 1 __ __ 4), which is is how the book represents that block.

The whole idea of spaces before and after is a tricky one, and hopefully when you look at pages 18-19 again, that will clarify it a bit more. But if not, let me know and I'll go into more detail.

Thanks!