Each person has 24 hours a day, so you better make a choice about how you will spend your time in a day.
My question is, If the bold letters here grammatical?
It comes really close, so good job!
To make it grammatical, you could use this:
Each person has 24 hours in a day, so you better make a choice about how you will spend your time in the day.
Or instead of "in the day", you could use "each day":
Each person has 24 hours in a day, so you better make a choice about how you will spend your time each day.
or if you want to talk about today specifically, which would change the meaning from the original sentence, you could say today":
Each person has 24 hours in a day, so you better make a choice about how you will spend your time today.
There was only one, really simple thing that necessarily needed to be changed in the original sentence, but there were three changes that ended up getting made:
1) 24hours -> 24 hours:
When you combine a number with a measurement, like hours, grams, or kilometers, you use separate words for the number and for the measurement. I 'm not sure about Tagalog, but this is different from Japanese and may be different from other, nearby languages.
2) a day -> in a day:
The phrase "24 hours a day" is usually used when you're talking about how often something happens, how often it's a certain way, how long it stays a certain way, etc. So if a store never closes, you could say that it's "open 24 hours a day".
When you use it here though, you're talking about how much time someone has, not how often/long something is or happens. So kind of like how you have "12 inches in a foot" and "3 feet in a yard", you also have "24 hours in a day".
Technically it's probably grammatically correct to say, "Each person has 24 hours a day," but usually you would go ahead and put the extra word in there.
3) in a day -> today / in the day / each day
Kind of like #2, technically the original sentence is grammatically correct here, but it's more common to use one of the other phrases, depending on exactly what you mean. If you use "today", that means you're telling them to make the choice about the day today specifically.
If you use the words "in the day", this is kind of interesting, because this is taking the phrase "in a day" and suddenly trying to do something different here. Why would you use "in a day" in #2, but "in the day" in #3? The difference here is the focus is not on all of the days in general, like it is in #2, but the focus is on each indidvidual day. If you say that there are "24 hours in a day", you are focused on a length of time much greater than a day. When you say "spend your time in the day" at the end of this sentence though, even though you're still kind of talking about a larger length of time, you're also talking about how that person or those people take the "24 hours in a day" and use all of those "24 hours". The focus here is on a 24-hour / one day timespan, so because of the context and the sentence as a whole, we're using a different article.
If you use the phrase "each day", it means the same thing as if you said "in the day". It's just a different way to say the same thing, in this particular sentence. But using the word "today" would mean something a little different.
No, your sentence is not grammatical or idiomatic.
The store is open 24 hours a day per day
You can accomplish much in a day. in the time span of a day
There are only 24 hours in a day. in the time span we call a "day"
They visited London for a week and planned what sights to see each day.
on the individual days of their week-long vacation, day by day