A skin care company had 1,500 people try a new acne cream. Nine people had a mild reaction the formula is then improved and those 1,500 people try the new cream only 4

The percent decrease in number of allergic reactions is 55%

Step-by-step explanation:

Only 4 of them had a mild allergic reaction. What is the percent decrease in number of allergic reactions?

Percent of allergic people= Allergic people/ Total people * 100

                                         = 9/1500* 100

                                         = 0.6 %

IT means that out of 1000 people only 6 persons are allergic to the cream.

New Percent of allergic people= Allergic people/ Total people * 100

                                         = 4/1500* 100

                                         = 0.267 %

It means that out of 1000 people only 2.67 persons are allergic to the new improved cream.

Difference between Percentage = Old Percentage- New Percentage

                                                      = 0.6 %- 0.267%

                                                       =0.333%

Decrease= 0.333% = 0.333/100

In every thousand people 3.33 people are free of allergic reactions from those 6 allergic people.

Percentage Decrease= Decrease/ Total * 100

                        = 0.333/ 0.6 *100

                           = 0.55*100

                            = 55 %

The percent decrease in number of allergic reactions is 55%

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step-by-step explanation: