How many grains of rice is 20 feet?
20 feet is roughly 871 grains of rice laid end to end.
That's roughly
871grains of rice laid end to end
Assuming one grain of rice is about a quarter inch long (7 mm, if you insist).
Also equal to
The math
One grain of rice is about a quarter inch long, or 7 mm in metric. 20 feet is 6.1 m. Divide one by the other:
6.1 m ÷ 0.007 m ≈ 871 grains of rice
Yes, we did the math in metric. Someone had to.