Question 34·Easy·One-Variable Data Distributions; Measures of Center and Spread
Cupcakes Sold in One Workweek
| Day | Number of cupcakes sold |
|---|---|
| Monday | 72 |
| Tuesday | 68 |
| Wednesday | 75 |
| Thursday | 70 |
| Friday | 65 |
The table above shows the number of cupcakes a bakery sold each day from Monday through Friday. Based on the data, what is the mean number of cupcakes sold per day, to the nearest whole cupcake?
For mean (average) questions on the SAT, quickly list or highlight the values, add them efficiently by grouping numbers that form easy sums (like making multiples of 10), and then divide by the count of data points. Always double-check that you’re dividing by the correct number of items and see whether any rounding is actually needed before matching your result to the answer choices.
Hints
Identify what the question is asking for
The question is asking for the mean number of cupcakes sold per day. How do you usually calculate the mean of several numbers?
Combine the daily values
Write down all five daily sales and add them together in one sum. You might find it easier to group numbers that add to round tens.
Use the number of days correctly
After finding the total cupcakes sold, what should you divide by to get the mean per day? Make sure you are dividing by the number of days, not by something else.
Check if you need to round
Once you divide, see whether the result is already a whole number or if you need to round it to the nearest whole cupcake.
Desmos Guide
Calculate the mean with a single expression
In Desmos, type the expression (72 + 68 + 75 + 70 + 65) / 5 and press Enter. The value Desmos displays is the mean number of cupcakes sold per day; choose the answer option that matches this value.
Step-by-step Explanation
Recall the formula for mean
The mean (average) of a set of numbers is found by adding all the values together and then dividing by how many values there are.
So here:
- Add the cupcakes sold each day from Monday to Friday.
- Divide that total by the number of days, which is .
Add the numbers of cupcakes sold each day
Add the daily sales:
Group them to make the addition easier:
So a total of cupcakes were sold from Monday through Friday.
Divide the total by the number of days
Now divide the total number of cupcakes by the number of days (5):
The mean number of cupcakes sold per day is , which matches answer choice C.