Of these, the numbers whose sum of the digits also equal 18, are 198, 288, 378, 396, 468, 486, 558, 576, 594, 648, 666, 684, 738, 756, 774, 792, 828, 846, 864, 882, 918, 936, 954, 972 and 990, which are 25 in number.
Check for a few numbers:
198 = 1 + 9 + 8 = 18
288 = 2 + 8 + 8 = 18
378 = 3 + 7 + 8 = 18
396 = 3 + 9 + 6 = 18
468 = 4 + 6 + 8 = 18 and so on.
Answer:
25 three-digit multiples of 18 have the sum of the digits also equal 18.
To find:
How many three-digit multiples of 18 have the sum of the digits also equal 18
Step-by-step explanation:
The three-digit multiples of 18 are 108, 126, 144, 162, 180, 198, 216, 234, 252, 270, 288, 306, 324, 342, 360, 378, 396, 414, 432, 450, 468, 486, 504, 522, 540, 558, 576, 594, 612, 630, 648, 666, 684, 702, 720, 738, 756, 774, 792, 810, 828, 846, 864, 882, 900, 918, 936, 954, 972 and 990.
Of these, the numbers whose sum of the digits also equal 18, are 198, 288, 378, 396, 468, 486, 558, 576, 594, 648, 666, 684, 738, 756, 774, 792, 828, 846, 864, 882, 918, 936, 954, 972 and 990, which are 25 in number.
Check for a few numbers:
198 = 1 + 9 + 8 = 18
288 = 2 + 8 + 8 = 18
378 = 3 + 7 + 8 = 18
396 = 3 + 9 + 6 = 18
468 = 4 + 6 + 8 = 18 and so on.
Answer:
25 three-digit multiples of 18 have the sum of the digits also equal 18.