Question

A store receives customer satisfaction ratings that range between 0 and 100. In the first 13 ratings the store received, the average customer satisfaction rating was 75. What is the least value the store can receive for the 14th rating and still be able to have an average of at least 84 for the first 21 ratings?

Answer 1

Explanation:

From the given information:

For the first 10 ratings, the average value is 75.

For maintaining the average of 84 ratings for the first 21st rating, we have:

Total rating for 21 units = 84 * 21 = 1764

For 10 units = 84 *10 = 840

Now, the initial 10 unit average = 75 * 10 =750

The first 10 unit + last 10 unit = 840 + 750 = 1590

The difference = 1764 - 1590 =174 unit

So, in the 14th rating, he has to go with 174 units.