Question

b= ( 2017 - 1/4 - 2/5 - 3/6 - ... - 2017/2020) : ( 1/20+1/25+1/30 +1/35 + ... +1/10100)

Answer 1

b = 15

mk làm bài này trong vòng 17 rồi đúng đó!!!

Answer 2

B=15. tớ làm rồi, đúng luôn đó !

Answer 3

nho ghi cach giai

Answer 4

\(B=\frac{2017-\frac{1}{4}-\frac{2}{5}-\frac{3}{6}-\frac{4}{7}-...-\frac{2017}{2020}}{\frac{1}{20}+\frac{1}{25}+\frac{1}{30}+\frac{1}{35}+...+\frac{1}{10100}}\)

\(B=\frac{1-\frac{1}{4}+1-\frac{2}{5}+1-\frac{3}{6}+...+1-\frac{2017}{2020}}{\frac{1}{20}+\frac{1}{25}+\frac{1}{30}+\frac{1}{35}+...+\frac{1}{10100}}\)

\(B=\frac{\frac{3}{4}+\frac{3}{5}+\frac{3}{6}+...+\frac{3}{2020}}{\frac{1}{20}+\frac{1}{25}+\frac{1}{30}+...+\frac{1}{10100}}\)

\(B=\frac{3\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+...+\frac{1}{2020}\right)}{\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{5.7}+...+\frac{1}{5.2020}}\)

\(B=\frac{3\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+...+\frac{1}{2020}\right)}{\frac{1}{5}\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+...+\frac{1}{2020}\right)}\)

\(B=\frac{3}{\frac{1}{5}}\)tức \(3:\frac{1}{5}=3.5=15\)

Vậy B=15