# Is it correct to use “happen once out of ten” in my situation?

I had an ipad and it sometimes won't boot normally but Not every time. It is only one time not to boot after I press power button to boot for 10 times.

Could I describe this situation with the following sentence for apple's maintenance engineer?

Sometimes, the ipad cannot boot normally with black screen after I press power button.(happened once out of ten)

Or (once every ten times)

If not, please tell me how to say.

• How many times have you done this? When you say "once out of ten times" do you mean you've restarted your iPad exactly ten times and this has happened one time or do you mean you've restarted it 40 times and it's happened 4 times? Which of the two is the case will determine the correct way of phrasing this.
– Catija
May 4, 2015 at 16:34
• Hi Catija, thanks for your reply. Could you please tell me the both of usage? Any suggestion would be appreciated. Could I use "about 10% of the time" for 1st situation and use "One time out of ten" for 2nd situation. May 5, 2015 at 1:11

I agree with the suggestion user 3169 gave: One time out of ten it is a commonly used expression (see definition 14 in LDOCE definition of time)

Your other suggestion to phrase it sounds good:

It happens once every ten times.

It is used for something that happens repeatedly, sometimes used for regular events(see def. 2).

There is evidence of usage (which I found in a Google books search).

I found some examples of usage for:

once in 10 times

but these were mostly for probability, and you want to express frequency or a proportion.

10% of the time

or, slightly rephrased

in 10% of the cases/attempts

also sound good.

**Side note: the use of present simple indicates a repeated problem. If you use past simple in combination with on(c)e out of 10 to say: It happened once, out of 10 times or It happened one time out of 10 this would indicate that you have tried 10 times and encountered this problem only once.On the other hand once every n times indicates that the problem happened repeatedly, regardless of the verb tense you use.

I would say:

One time out of ten, the ipad will not boot normally, with a black screen after I press the power button.