3 rim - 3 lusin + 50 lembar=........lembar

3 rim=3×500=1500
3 lusin=3×12=36
jadi ,jawabannya adalah:
1500-36+50=1464+50=1514 lembar

1 lusin = 12 buah
1 gross = 144 buah = 12 lusin
1 kodi = 20 buah
1 rim = 500 lembar

3 rim - 3 lusin + 50 lembar
3 × 500 = 1500
3 × 12 = 36
50

1500 - 36 + 50 = 1514 lembar