Treating a city's water supply to remove any bacteria and impurities as clean and hygenic water supplies benefits the public/society.
So we know that 40% of the 35 males are wearing sungalsses
40%=40/100=2/5
'of' means multiply
2/5 times 35 malses are wearing sunglasses
70/5=sunglasses
14=sunglasses
so 14 out of 56 to percent
14/56=0.25
answer is 25%
Smoking alichal and eating large portions of food
