397. A and B set out from the same place, in the same direction; A travels uniformly 18 miles per day, and, after 9 days, turns and goes as far as B has traveled during those 9 days; he then turns again, and, pursuing his journey, overtakes B 22½ days after the time they first set out. Required the rate at which B uniformly traveled.

398.

To a word of consent join the first half of fright,

Next subjoin what you never beheld in the night;

Now, these rightly connected, we quickly obtain

What numbers have seen, but will ne’er see again.

399.