Using numbers in sentences

I recently had the following question on an English Composition exam and missed it. Perhaps someone can tell me the correct answer, but more importantly....WHY.

Select the sentence that is structurally and grammatically correct.....

1. There were five cars and 7 planes.

2. There were 5 cars and 7 planes.

3. There were five cars and seven planes.

4. There were five cars and eleven planes.

Hello Guest

As Jacklong pointed out, all the sentences you presented are grammatical. The problem would be not their grammaticality but whether they are good or not from the viewpoint of writing styles. The sentence #1 is too bad in the style because this sentence is using an Arabic numeral and an English word numeral in a mixed manner. I personally like the style of #2, but the style is the one used rather in math or arithmetic textbooks.

paco

I realize this posting is old, but thought I'd add my two cents.. All I have to go on is my highschool English education. I'm trying to find a better reference to
back this up:

The rule is: Whenever a number in a sentence is less than 10, it should be expressed as a word. Any number greater than 10 should be expressed in a sentence with numerals.

So:

1) is incorrect because the '7' is not expressed as a word.
2) is incorrect because the '5' and the '7' are not expressed as a word.
4) is incorrect because the number '11' is greater than 10 and should be expressed with numeric characters.

3) is correct because both numbers are expressed as a word.

If I find a decent reference for where on earth my English teachers got this rule from, I'll post it.

Cheers, Liz

3. In writing the number below 10 can be written as words. 3 is consistent and both values are less than 10. I know this is late, but I still hope it helps.

Jade

Actually sentence #3 is the only one that is correct.  According to the style guides at the University of Colorado at Boulder, this is the rule:

In General The following guidelines apply to the majority of CU writing except for scientific, statistical, technical, and mathematical writing.

• Spell out one to nine. Use numerals for 10 and above.
  When she was a child she wanted to be a professor when she grew up. When she turned 21, she realized that she'd rather be a flight instructor.

I have seen this rule established and used in other resources, also.

I hope this helps!

 

Thanks.

Marilyn

Plano, TX