There are about 37 trillion (37,000,000,000,000) cells in the human body.

(a) if each cell were as big as the tip of a fine point pen tip (0.5 mm), and the 37 trillion pen tips
were set out side-by-side in a long line, how many miles long would that line be? (there are
1000mm in 1 m, 1000 m in a km, and 1.609 km in a mile.)

(b) the average distance from the earth to the moon is 238,900 miles. how many times could
you stretch the line of pen tips from the earth to the moon?