If the fifth sale is on headphones, then the sale on microwaves could be earlier than the sale on

Zia on June 7, 2020

Explanation

Can someone please explain the right answer?

Reply

on June 7, 2020

Hello @zia305,

The third and fourth rules combine to give us two basic diagrams:

T _ _ _ _ _ _
1 2 3 4 5 6 7

R _ _ _ _ _ T
1 2 3 4 5 6 7

This question tells us that the fifth sale is on headphones. In order to separate S from H according to rule 1, there is only one option for S, which is week 2. This allows us to place P in week 3.

T S P _ H _ _
1 2 3 4 5 6 7

R S P _ H _ T
1 2 3 4 5 6 7

We also know that L is before H.

T S P L H _ _
1 2 3 4 5 6 7

R S P L H _ T
1 2 3 4 5 6 7

This gives us only a few options for M. In diagram 1, it could be in 6 or 7, before or after R.

T S P L H R/M R/M
1 2 3 4 5 6 7

In diagram 2 it must be in spot 6, before T.

R S P L H M T
1 2 3 4 5 6 7

T is not one of the answer choices here, so the sale of microwaves can only be earlier than the sale on refrigerators, as seen in diagram 1. This is why D is correct.