SOLUTION: At a store, customers are randomly selected to participate in a survey. On Friday, there were 500 customers at the store. Out of all those people, 90 were selected to participate i

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Question 1105665: At a store, customers are randomly selected to participate in a survey. On Friday, there were 500 customers at the store. Out of all those people, 90 were selected to participate in the survey. On Saturday, the store manager expects 700 customers in the store. If the probability of being selected to participate in the survey on Saturday is the same as it was on Friday, how many customers will be selected to participate in the survey on on Saturday?
Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


This is a simple ratio and proportion problem: 90 out of 500 is the same as how many out of 700.

90%2F500+=+x%2F700
18%2F100+=+x%2F700
x+=+18%2A7+=+126

126 out of the 700 customers will be surveyed.

Another way to think about it is using the ratio of the numbers of people on the two days:
700%2F500+=+7%2F5
so the number of people surveyed on Saturday should be 7/5 the number surveyed on Friday:
%287%2F5%29%2A90+=+%287%2A90%29%2F5+=+7%2A18+=+126