Question

[Lưu Tuệ Phương]

Rút gọn phân số sau:

\(M=\frac{\text{2 . 6 . 10 + 4 . 12 . 20 + 6 . 18 . 30 + ..... + 20 . 60 . 100 }}{\text{1 . 2 . 3 + 2 . 4 . 6 + 3 . 6 . 9 + ..... + 10 . 20 . 30}}\)

Answer 1

[Greninja]

\(M=\frac{2.6.10+4.12.20+6.18.30+...+20.60.100}{1.2.3+2.4.6+3.6.9+...+10.20.30}\)

\(=\frac{2.6.10.\left(1+2+3+...+10\right)}{1.2.3.\left(1+2+3+...+10\right)}\)

\(=20\)