Question

B=\(\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}\)

Answer 1

\(\frac{13}{4}\)

Answer 2

\(B=\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}\)

\(\Rightarrow\frac{B}{7}=\frac{5}{2.7}+\frac{4}{7.11}+\frac{3}{11.14}+\frac{1}{14.15}+\frac{13}{15.28}\)

\(\Rightarrow\frac{B}{7}=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{15}+\frac{1}{15}-\frac{1}{28}\)

\(\Rightarrow\frac{B}{7}=\frac{1}{2}-\frac{1}{28}\)

\(\Rightarrow\frac{B}{7}=\frac{14}{28}-\frac{1}{28}\)

\(\Rightarrow\frac{B}{7}=\frac{13}{28}\)

\(\Rightarrow B=\frac{13}{28}.7\)

\(\Rightarrow B=\frac{13}{4}\)