Chip A is 80% as fast as Chip B

[Don Karnage]

Hello everyone.
The expression: "Chip A is 80% as fast as chip B". This means that chip A is 80% faster, or has only 80% of the speed of B (thus, A is 20% slower than B)?

(Note from moderator - Don Karnage, please stop editing this post. It needs to be left in its original form so the responses make sense.)

 

[jutfrank]

The latter.

If you meant the former, you'd say Chip A is 80% faster than Chip B.

 

[emsr2d2]

Hello, everyone.

Please consider the expression sentence no colon here "Chip A is 80% as fast as chip B". This means Does this mean that chip A is 80% faster, or has only 80% of the speed of B (thus, A is 20% slower than B)?

Please note my corrections above. You didn't give us an expression; you simply gave us a sentence.

 

[probus]

Hello @Don Karnage and welcome to the forum. This forum is devoted to English, but nevertheless I cannot resist pointing out that your math is faulty. If A is 20% slower than B (four fifths) then B is 25% faster than A (five fouths).

Please note that this thread has been moved to the forum section it belongs in.

 

[jutfrank]

I cannot resist pointing out that your math is faulty.

It's true that if A is 80% as fast as B (in other words A is 20% slower than B), then B is 25% faster than A, but Don Karnage hasn't said anything that contradicts that. There's no faulty math.

(This thread is in the wrong section, by the way.)

 

[probus]

@jutfrank Thanks for that. I've moved the thread.

Perhaps I didn't clearly and correctly explain the math error, but I won't bother fixing that, so we can just stick to English.

 

[jutfrank]

@probus—I'm genuinely very curious to know where you think the math error is.

 

[tedmc]

You are comparing the attribute of speed. I think this is clearer and more direct:

The speed of Chip A is 80% that of Chip B.

 

[Don Karnage]

Hello @Don Karnage and welcome to the forum. This forum is devoted to English, but nevertheless I cannot resist pointing out that your math is faulty. If A is 20% slower than B (four fifths) then B is 25% faster than A (five fouths).

Please note that this thread has been moved to the forum section it belongs in.

Thanks to all of you for your responses. Thus, I must admit that Google translator translates it in the wrong way.
I agree that I could have been incorect in choosing a forum section.
Yesterday I edited my post according to "emsr2d2" remark and saved changes, but today I saw my post in its original form. I will try to edit it one more time.

 

[emsr2d2]

Yesterday I edited my post according to "emsr2d2" remark and saved changes, but today I saw my post in its original form. I will try to edit it one more time.

I know you did! I changed it back to the original version (and I've just changed it back again!) Please don't edit posts after people have responded to them. It makes the responses look nonsensical. Just note the correct version and avoid making the same errors again.

 

[SoothingDave]

@probus—I'm genuinely very curious to know where you think the math error is.

Chip A is 80% of the speed of chip B
Chip B is 125% of the speed of chip A.

If A is 80, then B is 100. 80% of 100 is 80. 25% of 80 is 20. 80 + 20 = 100. 125% of 80 is 100.

 

[jutfrank]

Chip A is 80% of the speed of chip B
Chip B is 125% of the speed of chip A.

If A is 80, then B is 100. 80% of 100 is 80. 25% of 80 is 20. 80 + 20 = 100. 125% of 80 is 100.

That's all correct, yes. But there's no error anywhere.

A is 80% as fast as B
A is 20% slower than B

These expressions are synoymous. Are you implying that that's not the case?

 

[probus]

That's all correct, yes. But there's no error anywhere.

A is 80% as fast as B
A is 20% slower than B

These expressions are synoymous. Are you implying that that's not the case?

Yes, I am. And so (I believe) is @SoothingDave. The two expressions are synonymous only to those who are mathematically challenged. In fairness I admit that a great many folks are mathematically challenged.

This whole discussion puts me in mind of the legendary Victorian dowager whose opinion was that arithmetic is a form of low cunning.

 

[jutfrank]

You're getting something wrong with the logic, probus, but I can't yet see what it is. How much slower than B (percentage-wise) do you consider A to be? I hope you're not going to say 25%!

Let's say that A is 80 and B is 100.

Therefore:

1) A is 80% of the speed of B.
2) B is 25% faster than A. (In other words 125% the speed of A.)
3) A is 20% slower than B.

The difference between 80 and 100 is 20.
20 is 20% of 100.

The maths here is not hard, so I assume there's something we disagree on in terms of the logic. I'm waiting for someone to tell me what it is because I'm genuinely curious to know what's being misunderstood.

 

[Tarheel]

Eighty is 80% of one hundred. Twenty is 25% of eighty.

 

[jutfrank]

Twenty is 25% of eighty.

It appears you're making the same error as probus.

Yes, 20 is 25% of 80 but that's not the correct calculation here. You're getting things the wrong way round. The sentence A is 20% slower than B concerns the speed of A in relation to B, not the speed of B in relation to A. The calculation you have to make is this: 20 is 20% of 100.

I'll put it as clearly as I can:

Imagine a car travelling at 100 mph, then decelerating to go 20% slower. It's then travelling at 80 mph, which is 80% as fast as it was before.