A company that makes hair-care products had 9 comma 000 people try a new shampoo. Of the 9 comma 000 people, 72 had a mild allergic reaction. What percent of the people had a mild allergic reaction?

The percent of people with mild allergic reaction is 0.8%

Step-by-step explanation:

The company has 9000 people, and 72 people have mild allergic reaction.

The fraction of people with mild reaction is 72 over 9000, i. e. 72/9000

72 and 9000 are multiple of 9, therefore reducing both by 9, we will have 8/1000.

8 and 1000 are both multiple of 4, so we will reduce both by 4, we will have

2/250.

2/250 can still be reduced by to, therefore we will have 1/125

To get the percentage, we will now multiply the fraction 1/125 by 100, we will have 100/125

Reduce both 100 and 125 by 25 which will make 4/5

then, turning 4/5 to decimal, we will have 0.8%

Therefore 0.8% of people had a mild allergic reaction