Question

Gaseste numerele naturale de 3 cifre care au cifra zecilor egala cu dublul cifrei unitatilor.

Answer 1

121, 142, 163, 184, 221, 242, 263, 284, 321, 342, 363, 384, 421, 442, 463, 484, 521, 542, 563, 584, 621, 642, 663, 684, 721, 742, 763, 784, 821, 842, 863, 884, 921, 942, 963, 984

Answer 2

abc-numar natural de doua cifre;
⇒b=2c⇒c∈[1,2,3,4];
⇒b∈[2,4,6,8];
⇒a∈[1,2,3,4,5,6,7,8,9];
⇒numerele gasite sunt:121,142,163,184,etc.⇒9·4=36 de numere;