A = 1
B = 3
C = 9
D = 17

1 lb = A
2 lbs + A = B
3 lbs = B
4 lbs = A + B
5 lbs + A + B = C
6 lbs + B = C
7 lbs + B = A + C
8 lbs + A = C
9 lbs = C
10 lbs = A + C
11 lbs + A = B + C
12 lbs = B + C
13 lbs = A + B + C
14 lbs + B = D
15 lbs + B = A + D
16 lbs + A = D
17 lbs = D
18 lbs = A + D
19 lbs + A = B + D
20 lbs = B + D
21 lbs = A + B + D
22 lbs + A + B = C + D
23 lbs + B = C + D
24 lbs + B = A + C + D
25 lbs + A = C + D
26 lbs = C + D
27 lbs = A + C + D
28 lbs + A = B + C + D
29 lbs = B + C + D
30 lbs = A + B + C + D

8 ÷ (3 – (8 ÷ 3)) = 24

Mailbox

1/12 mile

Ten seconds is 1/6 of a minute and 1 minute is 1/60 of an hour, so 10 seconds is 1/360 of an hour.

If you graph her trip with the speed on the y-axis and the time on the x-axis, you get a triangle with height of 60 mph and width of 1/360 of an hour. To calculate the area of the triangle, you multiply 1/2 × 1/360 × 60 = 1/12.

29%

To read more about this, see the False Positive Paradox page on Wikipedia.

888 + 88 + 8 + 8 + 8 = 1,000