Question

[Kudo Shinichi]

Tìm số tự nhiên X , biết  a, 3/5 < x/6 < 4/5   b, 3/5 < 2/x < 4/5 

Answer 1

[Phan Thanh Tịnh]

a) \(\frac{3}{5}<\frac{x}{6}<\frac{4}{5}\)=> \(\frac{18}{30}<\frac{5x}{30}<\frac{24}{30}\)=> 18 < 5x < 24 => 5x = 20 => x = 20 : 5 = 4

b) \(\frac{3}{5}<\frac{2}{x}<\frac{4}{5}\)=> \(\frac{12}{20}<\frac{12}{6x}<\frac{12}{15}\)=> 20 > 6x > 15 => 6x = 18 => x = 18 : 6 = 3