Question

timx,y thuoc z biet:\(\frac{1}{18}<\frac{x}{12}<\frac{y}{9}<\frac{1}{4}\)

Answer 1

1/18 < x/12 < y/9 < 1/4.

Ta quy dong mau len co mau chung la 36: 2/36 < x.3/36 < y.4/36 < 9/36.

Suy ra: Vi 2<x<y<9 nen phai bang 3;4;5;6;7;8:

x.3          3          4          5           6           7            8

x             1        loai      loai          2         loai         loai

y.4          3          4          5           6           7            8

y           loai       1         loai        loai       loai          2

Suy ra ta co 3 truong hop:

TH1: x=1;y=1: 2/36 < 1.3/36 < 1.4/36 < 9/36

TH2: x=2;y=2: 2/36 < 2.3/36 < 2.4/36 < 9/36

TH3: x=1;y=1: 2/36 < 1.3/36 < 2.4/36 < 9/36