Gọi số đó là abc (a; b;c là các chữ số khác nhau)
=> abc = ab + bc + ca + ba + cb + ac
=> abc = a0 + b + b0 + c + c0 + a + b0 + a + c0 + b + a0 + c
=> abc = 2.aa + 2.bb + 2.cc
=> 100a + 10b + c = 22a + 22b + 22c
=> 78a = 12b + 21c < 12.9 + 21.9 = 297
=> a < 4 => a = 1;2 ; 3
Vì abc lớn nhất nên ta chọn a = 3 => 12b + 21c = 234
=> 4b + 7c = 78 .
Chọn b lớn nhất có thể : thử b = 9 => c = 6 Nhận
Vậy số lớn nhất đó là 396
gọi số đó là abc (a;b;c là các chữ số khác nhau)
suy ra abc =ab+bc+ca+ba+cb+ac
suy ra abc=a0+b+b0+c+c0+a+b0+a+b+a0+c
suy ra abc=2.aa+2.bb+2.cc
suy ra 100a+10b+c=22a+22b+22c
suy ra 78a=12b+21c<12.9+21.9=297
suy ra a<4suy ra a=1;2;3
vì abc lớn nhất nên ta chọn a =3suy ra 12b +21c=234
suy ra 4b +7c=78
chọn b lớn nhất có thể :thử b =9 suy ra c=6 (nhận)
vậy số đó là 396
396 đúng 100% sai mình chết luôn cho các cậu coi,k cho mình nhé
sai hết là 963!vì người ta hỏi so lon nhat co ma!
396 dung 100000000000000000000000000000000000000000000000000000% luc thi violympic minh giai roi
396 la dung 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%
Bạn nào trả lời là 963 là sai rồi vì tổng tất cả các chữ số của nó là 396 chứ ko phải là 963.Và đáp án của mình là 396 nha
396 đúng 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000-00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Đặng đức trí sai rồi bạn thử cộng các số có 2 c/s lập từ 3 số đó xem có ra 396 không
Gọi số phải tìm là (a ≠ b ≠ c)
Theo bài ra ta có:
=
100a + 10b + c = 10a + b + 10a + c + 10b + a + 10b + c + 10 c + a + 10c + b
100a + 10b + c = 22a + 22b + 22c
78a/ 12b = 21c
26a/ 4b = 7c
Vì: 26a chẵn, 4b chẵn, suy ra: c là số chẵn
Nếu: c = 0, ta có: 26a/ 4b = 0 (loại)
Nếu: c = 2, ta có: 26a/ 4b = 14. Suy ra: a = 1, b = 3. Suy ra: abc = 132
Nếu: c = 4, ta có: 26a/ 4b = 28. Suy ra: a = 2, b = 6. Suy ra: abc = 264
Nếu: c = 6, ta có: 26a/ 4b = 42. Suy ra: a = 3, b = 9. Suy ra: abc = 396
Nếu: c = 8, ta có: 26a/ 4b = 56 (loại)
Vì là số tự nhiên lớn nhất có 3 chữ số khác nhau nên số phải tìm là: 396
Đáp số 396.
