But 50 % slower is either 1.5 or twice as long, depending on whether the 50 % refer to an increase of the runtime or a decrease of throughput. 200 % slower is only unambiguous because the throughput can not decrease by more than 100 %.
Usually that’s “half as fast”. English has always had the terrible twos. Is biweekly twice a week or every two weeks.
I’ve been doing capacity planning lately and the whole deal with how we are bad at fractions came up again. If you have to spool up 10% more servers and then cut costs by 10%, you’re still slightly ahead. If you cut 10% and then later another 10% you have cut 19% of the original, not 20%.
