Question

Tìm a,b,c ( a, b, c là số tự nhiên)

 \(\overline{1abc}\) \(\times2=\overline{abc8}\)

 

Answer 1

Giải:

Ta có:

\(\overline{1abc}.2=\overline{abc8}\)

\(\Rightarrow\left(1000+\overline{abc}\right).2=10.\overline{abc}+8\)

\(\Rightarrow2000+2.\overline{abc}=10.\overline{abc}+8\)

\(\Rightarrow10.\overline{abc}-2.\overline{abc}=2000-8\)

\(\Rightarrow8.\overline{abc}=1992\)

\(\Rightarrow\overline{abc}=249\)

\(\Rightarrow a=2,b=4,c=9\)

Vậy a = 2, b = 4, c = 9

Answer 2

Ta có:

1abc x 2 = abc8

=> (1000 + abc) x 2 = abc0 + 8

=> 2000 + abc x 2 = abc x 10 + 8

=> 2000 - 8 = abc x 10 - abc x 2

=> 1992 = abc x 8

=> abc = 1992 : 8

=> abc = 249

Vậy a = 2; b = 4; c = 9