10 red hat+16 police mobile unit +37 yellow hat+13 white hat =257 yuan ②
①×3-②×2,
1 red hat, 1 police tactical unit, 1 yellow hat, 1 white hat cost177× 3-257× 2 = 531-514 =
Answer: 1 red hat, 1 police tactical unit, 1 yellow hat, 1 white hat cost 17 yuan.