Three fourths populations in Singaporeare are of Chinese origin.
3/4用尘谈are没错.
这些新雀兄拦加坡人是华裔,但是国籍并不顷胡是中国,所以要用of Chinese origin(华人,华裔)
Three forths of the population in Singapore are Chinese.
Three fourths populations in Singaporeare are the Chinese
3 /4 of Singaporean population is Chinese