Question

Determine the first three common multiples of 31, 20, and 18.

a) 120, 240, 360
b) 62, 40, 36
c) 20, 40, 62
d) 93, 35, 24

Answer 1

The first three common multiples of 31, 20, and 18 are 360, 720, and 1,080.

Step-by-step explanation:

The first three common multiples of 31, 20, and 18 are 360, 720, and 1,080.

To find the common multiples, we can find the multiples of each number and identify the multiples that are common to all three.

For 31, the multiples are 31, 62, 93, 124, 155, 186, 217, 248, 279, 310, 341, 372, 403, 434, 465, 496, 527, 558, 589, 620, 651, 682, 713, 744, 775, 806, 837, 868, 899, and so on.

For 20, the multiples are 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500, 520, 540, 560, 580, 600, and so on.

For 18, the multiples are 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, 198, 216, 234, 252, 270, 288, 306, 324, 342, 360, 378, 396, and so on.

The common multiples are the numbers that appear in all three lists. The first three common multiples are 360, 720, and 1,080.