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The sentence is:

あの店は今、3割引のセールをしています。

I suspect it means 30% , but maybe it means 33.3% which is 1/3?

In any case I don’t understand the logic behind this.

How would you say if the discount rate was 3% instead?
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2020-03-08T11:43:37.137
74882
2020-03-08T15:54:13.477
36722
question
meaning words usage nuances expressions
3割引 ＝3 %? 33.3 % ? 30 %?
> あの店は今、3割引のセールをしています。
>
> I suspect it means 30% , but maybe it means 33.3% which is 1/3?

Your suspicion is correct. わり and わりびき should be in the dictionary.

> In any case I don’t understand the logic behind this.

One wari = ten percent.

> How would you say if the discount rate was 3% instead?

さんパーセントオフ
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2020-03-08T11:51:48.030
74883
2020-03-08T11:51:48.030
2020-06-17T08:18:27.500
-1
74882
answer
> 「あの店は今、3割引のセールをしています。」 _"I suspect it means 30% , but maybe it means 33.3%
> which is 1/3?"_ _"In any case I don’t understand the logic behind this."_

According to
[コトバンク](https://kotobank.jp/word/%E6%8A%8A%E5%88%A9%E3%83%BB%E5%92%8C%E5%88%A9-2094433),
etymologically speaking,「割{わり}」comes from「把利・和利」 which was used for the unit
of tax.「把」 was defined as 1/10 of a bundle of rice harvest and some「把」was paid
to the mayor.

I am not sure where 「和利」 comes from. Anyway it turned out to be 「割{わり}」 which
was confused with the word 「分割{ぶんかつ}」 : "Division", "Partition", "Separation".

Since around then I think it had been used for the discount rate.

Now, it is not limited to the numeric value. We also have「学割」 which is the
contraction of 「学生割引」: "special discount for student" (I don't know if there
is any fixed discount amount for the student).

* * *

> How would you say if the discount rate was 3% instead?

3パーセント引き is fine(3パーセントオフ is also fine the same as the other answer. I think
we use only percentage for 3/100 discount.

* * *

It is a little bit different from the discount rate though. We count how many
times baseball player hit in Japanese professional baseball leagues. If you
hit 33 times in 100 opportunities, it is 33%. It is said 3割{わり}3分{ぶ}. We
normally have more than 100 opportunities. We add 厘 to describe
3割{わり}3分{ぶ}3厘{りん} for 333 hits in 1000 opportunities (See [打率{だりつ}:batting
average](https://ja.wikipedia.org/wiki/%E6%89%93%E7%8E%87).
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2020-03-08T15:54:13.477
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2020-03-08T15:54:13.477
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answer