Question

B=5/2.7+5/7.12+5/12.17+5/17.22+5/22.29

Answer 1

Sửa: 

\(B=\frac{5}{2.7}+\frac{5}{7.12}+\frac{5}{12.17}+\frac{5}{17.22}+\frac{5}{22.27}\)

Trả lời

\(B=\frac{5}{2.7}+\frac{5}{7.12}+\frac{5}{12\cdot17}+\frac{5}{17\cdot22}+\frac{5}{22\cdot27}\)

\(\Rightarrow B=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{12}+\frac{1}{12}-\frac{1}{17}+\frac{1}{17}-\frac{1}{22}+\frac{1}{22}-\frac{1}{27}\)

\(\Rightarrow B=\frac{1}{2}-\frac{1}{27}\)

\(\Rightarrow B=\frac{25}{54}\)

Vậy B=\(\frac{25}{54}\)