ITPEC IP April 2019 Question 1

(not A) and B and C — the black area lies inside both B and C, and outside A.

Read the region set by set:

• •it is inside circle B and inside circle C, so both B and C must hold: B and C
• •it is the part of that overlap that is not also in A (the centre where all three circles meet stays white), so not A must hold too

Every condition must hold at once, so all three are joined with AND: (not A) and B and C.

Answer (a)

Why not others:

• •(b) — B or C covers the whole of both circles, so this also selects the parts of B alone and of C alone that lie outside A
• •(c) — the OR selects everything outside A, including the empty background, plus the centre where all three circles overlap
• •(d) — selects everything except the part of A that lies in neither B nor C

Key rule: A region inside several circles is their AND, a region covering either circle is their OR, and a circle the region avoids enters as NOT; list what the shaded area is inside and outside of, then join those facts with AND.

Basic Theory · AI-written, may contain errors