The speed limit is 55 miles per hour on most highways. We want to find the ratio of Sam's speed to the US speed limit.
1: 55 mph 2: 55 mph 3: 11 hr mph / yd
. 1: 5 yd / hr .
.
' 55 mph RET ' 5 yd/hr RET /
The u s command cancels out these units to get a plain number. Now we take the logarithm base two to find the final answer, assuming that each successive pill doubles his speed.
1: 19360. 2: 19360. 1: 14.24
. 1: 2 .
.
u s 2 B
Thus Sam can take up to 14 pills without a worry.