Question

[BACHHONGHEO]

Tính M,biết: M=20/112+20/280+20/520+20/832

Answer 1

[Huế Nguyễn Thị]

\(M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}\)

\(M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}\)

\(M=\frac{20}{6}.\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)\)

\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)

\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{32}\right)\)

\(M=\frac{20}{6}\cdot\frac{3}{32}\)

\(M=\frac{5}{16}\)

Answer 2

[Chi Ben Mot Nguoi]

$M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}$

$M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}$

$M=\frac{20}{6}.\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)$

$M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)$

$M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{32}\right)$

$M=\frac{20}{6}\cdot \frac{3}{32}$

$M=\frac{5}{16}$