Question

20-18,6:(6 11/15- 4 3/20)
Помогите решить пожалуйста

Answer 1

ответ:

$\displaystyle \frac{64}{5}=12\frac{4}{5}=12,8$

решение:

$\displaystyle 20-18,6:(6\frac{11}{15}-4\frac{3}{20})=\frac{64}{5}=12\frac{4}{5}=12,8\\ \\1)20-\frac{93}{5}:(6\frac{11}{15}-4\frac{3}{20})=20-\frac{93}{5}:(\frac{101}{15}-4\frac{3}{20})=20-\frac{93}{5}:(\frac{101}{15}-\frac{83}{20})\\ \\18,6=\frac{186}{10}=\frac{93}{5}\\ \\6\frac{11}{15}=\frac{6*15+11}{15}=\frac{90+11}{15}=\frac{101}{15}\\ \\4\frac{3}{20}=\frac{4*20+3}{20}=\frac{80+3}{20}=\frac{83}{20}$

$\displaystyle 2)20-\frac{93}{5}:\frac{31}{12}\\ \\\frac{101}{15}-\frac{83}{20}=\frac{404-249}{60}=\frac{155}{60}=\frac{31}{12}\\ \\3)20-\frac{93}{5}*\frac{12}{31}=20-\frac{3}{5}*12\\ \\4)20-\frac{36}{5}=\frac{64}{5}=12\frac{4}{5}=12,8\\ \\ -\frac{3}{5}*12=-\frac{3}{5}*\frac{12}{1}=-\frac{3*12}{5*1}=-\frac{36}{5*1}=-\frac{36}{5}$