Answer:
32/27
Step-by-step explanation:
16/21 × 20/24 × 28/15
16/21 × 5/6 × 28/15
16/3 × 5/6 × 4/15
16/3 × 1/6 × 4/3
8/3 × 1/3 × 4/3
32/27 is your answer
