Question

[Lý Trần Minh Châu]

Tính giá trọ sau bằng cách hợp lí: \(\frac{240x50+48x100}{42x37+21x126}\)

Answer 1

[Phạm Trà Giang]

Đặt \(A=\frac{240\cdot50+48\cdot50}{42\cdot37+21\cdot126}=\frac{48\cdot5\cdot50+48\cdot50}{21\cdot2\cdot37+21\cdot126}\)

\(\Rightarrow A=\frac{48\cdot250+48\cdot50}{21\cdot74+21\cdot126}=\frac{48\cdot\left(250+50\right)}{21\cdot\left(74+126\right)}\)

\(\Rightarrow A=\frac{48\cdot300}{21\cdot300}=\frac{48}{21}=\frac{16}{7}\)