Answer:
168
Step-by-step explanation:
first, split both 840 and 24 into there primes.
840=2×2×2×3×5×7
24=2×2×2×3
therefore any multiples of 24 must have those factor.
so, factors of 840 that are multiples of 24 are
2×2×2×3=24
2×2×2×3×5=120
2×2×2×3×7=168
2×2×2×3×5×7=840
there the answer is 168
