Answer:
496
Explanation:
Start by writing out the multiples of each number
31 62 93 124 155 186 217 248 279 310 341 372 403 434 465 496
16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256 272 288 304 320 336 384 400 416 432 448 464 480 496
4 8 12 16 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84...496
Once you find the least common multiple for 31 and 16, it should be the same lcm for 4. (4 is a factor of 16)