Question

[Phuong Lan Thong Minh]

Tim so co 3 chu so co tong cac chu so la 20 va ti so giua chu so hang tram voi chu so hang don vi la 2 , con chu so hang chuc bang chu so hang tram

Answer 1

[Nghị Hoàng]

Gọi số đó là abc (a>0;a,b,c<10)

Ta có:

   a=2c và a=b \(\Rightarrow\)b=2c

a+b+c=20

2c+2c+c=20

5c=20

c=4

=>a=8

Vậy abc=884 

Answer 2

[Phuong Lan Thong Minh]

Ta co so do :

chu so hang tram [---------]-----------]

chu so hang chuc [----------]-----------]      [   20  ]

chu so hang don vi [----------]

chu so hang don vi la

20 : [2 + 2 +1 ]= 4

chu so hang tram va chuc la

4 x 2 = 8

so phai tim 884