IMO 1987 LL VIE72

Is it possible to cover a rectangle of dimensions m imes n with

imolonglistmathematicsolympiad

IMO 1987 LL VIE72

Origin: VIE

Problem

Is it possible to cover a rectangle of dimensions m \times n with bricks that have the trimino angular shape (an arrangement of three unit squares forming the letter L) if: (a) m \times n = 1985 \times 1987; (b) m \times n = 1987 \times 1989?