\(240:1+240:2+240:3+240:6\)
\(=240+120+80+40\)
\(=360+120\)
\(=480\)
⇒ Chọn A
240:1+240:2+240:3+240:6
=240.1+240.1/2+240.1/3+240.1/6
=240(1+1/2+1/3+1/6)
=240.(1+1)
=240.2=480
Chọn A
\(240:1+240:2+240:3+240:6\\=240+240\cdot \dfrac{1}{2}+240\cdot \dfrac{1}{3} +240\cdot \dfrac{1}{6}\\=240\cdot \Big(1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6} \Big)\\=240\cdot \Big(\dfrac{6}{6}+\dfrac{3}{6}+\dfrac{2}{6}+\dfrac{1}{6} \Big)\\=240\cdot\dfrac{12}{6}\\=240\cdot 2\\=480\\\Rightarrow Chọn.A\)