Four friends A, B, C and D live in a same locality. The house of B is in the…

In a direction-sense puzzle, a strict East/West statement between two points means they share the same latitude (north-south position matches), while a strict North/South statement means they share the same longitude (east-west position matches). Placing everyone on one coordinate grid, one axis-fix at a time, lets you read off the final compound direction between any two people.

Applying this to the given facts:

1. Fix A at the origin. Since B's house is east of A's house, B lies on A's latitude, to A's right.

2. Since B's house is north of C's house, C lies on B's longitude, directly below B -- further down than A.

3. Since C's house is west of D's house, D lies on C's latitude, directly to C's right -- further right than B, which is already right of A.

4. Combining these, D sits to the right of A (east) and below A (south) at the same time.

Cross-check: retracing the same chain the other way -- from A, move east to B's longitude, then further south to C's latitude, then further east again to D's longitude -- lands on the same relative position: right of and below A. Both routes agree, so D's house lies South-East of A's house.