Obsahuje 2788

kolik čísel od 0 do 999 obsahuje alespoň jednu číslici 5?

Správná odpověď:

n = 271

Postup správného řešení:

5, 15, 25, 35, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 65, 75, 85, 95, 105, 115, 125, 135, 145, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 165, 175, 185, 195, 205, 215, 225, 235, 245, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 265, 275, 285, 295, 305, 315, 325, 335, 345, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 365, 375, 385, 395, 405, 415, 425, 435, 445, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 465, 475, 485, 495, 500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542, 543, 544, 545, 546, 547, 548, 549, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559, 560, 561, 562, 563, 564, 565, 566, 567, 568, 569, 570, 571, 572, 573, 574, 575, 576, 577, 578, 579, 580, 581, 582, 583, 584, 585, 586, 587, 588, 589, 590, 591, 592, 593, 594, 595, 596, 597, 598, 599, 605, 615, 625, 635, 645, 650, 651, 652, 653, 654, 655, 656, 657, 658, 659, 665, 675, 685, 695, 705, 715, 725, 735, 745, 750, 751, 752, 753, 754, 755, 756, 757, 758, 759, 765, 775, 785, 795, 805, 815, 825, 835, 845, 850, 851, 852, 853, 854, 855, 856, 857, 858, 859, 865, 875, 885, 895, 905, 915, 925, 935, 945, 950, 951, 952, 953, 954, 955, 956, 957, 958, 959, 965, 975, 985, 995,