Correct

三十

/ sān shí / 
Strokes

Definition

thirty/30

Example

As a Numeral

thirty; thirtieth

1
Dìsānshí
第三十

thirtieth

2
Sānshí
三十
suì
岁
shēngrì
生日

one's thirtieth birthday

3
Sānshí
三十
niándài
年代

in the thirties; in the 30s

4
Sānshí
三十
suì
岁
chūtóu
出头
de
的
nánshì
男士

man in his early thirties