Answer
$100011111$
Work Step by Step
$287_{10} = ((1 \times 256) + (0 \times 128) + (0 \times 64) + (0 \times 32) + (1 \times 16) + (1 \times 8) + (1 \times 4) + (1 \times 2) + (1 \times 1))_{10} = ((1 \times 2^{7}) + (0 \times 2^{6}) + (0 \times 2^{5}) + (0 \times 2^{5}) + (1 \times 2^{4}) + (1 \times 2^{3}) + (1 \times 2^{2}) + (1 \times 2^{1}) + (1 \times 2^{0}))_{10} = 100011111_{2}$