Answer:
48
Explanation:
821 rounded down to 800
17 rounded up to 20
820/20 =41
20x41=820
17 x 41 = 697
17 x 51 = 867
Midpoints
697+867/2 = 782
41 +51/2 = 46
46 x 17 = 782
47 x 17 = 799
48 x 17 =816
49 x 17 =833
50 x 17 =850
So, the highest number is 48.
The closest we can get is 48 x 17=816 & without going over 821.