Given;
16 men with helmet
19 women without helmet
To get the total number of people on site, we need to know either the total number of men and women or total number of people with helmet and people without helmet.
Statement 1--> There are 21 men on the construction site. This means that 5 men do not have helmet.
Also, there are 19 women without helmet but no information on the number of women with helmet or total no. of women.
Hence, Statement 1 is INSUFFICIENT
Statement 2 --> There are 24 people that do not wear helmets on the construction site. Out of the 24, 19 of them are women and 5 of them are men but there is no information on the total number of people with helmet. Hence, statement 2 is INSUFFICIENT.
Combining both statement together, we know the total number of men, but we do not know the total number of women.
Also, we know the total number of people without helmet but we do not know the total number of people with helmet.
Hence, the two statement together are INSUFFICIENT...
OPTION E is the correct answer.