Mean - ISEE Middle Level Quantitative Reasoning

Card 0 of 20

Question

In a group of 4 books, the average number of pages is is 10. Juan adds a book with 20 pages to the group. What is the new average number of pages?

Answer

If the average of 4 books was 10, then the total number of pages was $4\times10 =40$ . Adding in the 20 new pages, but now dividing by 5 you get .

Compare your answer with the correct one above

Question

Give the mean of the data set (nearest tenth, if applicable):

$\left { 56,78,98,85,77,73 \right }$

Answer

Add the six elements and divide the sum by 6:

$467 \div 6 \approx 77.8$

Compare your answer with the correct one above

Question

Give the mean of the following data set:

$\left {1, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 9, 10 \right }$

Answer

Since there are 16 elements, divide their sum by 16 to get the mean:

$(1+ 2+ 3+ 3+ 4+ 4+ 4+ 5+ 5+ 6+ 6+ 6+ 6+ 7+ 9+ 10) \div 16 = 81 \div 16 = 5.0625$

Compare your answer with the correct one above

Question

Find the mean of this set of numbers:

54, 41, 99, 120, 66.

Answer

Firrst, add the numbers:

Then, divide by the amount of numbers in the set:

$380\div 5=76$

Answer: The mean is 76.

Compare your answer with the correct one above

Question

Find the average of this set of numbers:

521, 834, 754, 902, 899

Answer

First, add all the numbers in this set:

Divide, 3910 by the total amount of numbers in the set:

$3910\div 5=782$

Answer: The average is 782.

Compare your answer with the correct one above

Question

Find the mean in this set of numbers:

5570, 4886, 5226, 4120, 6561, 4120, 6008

Answer

First, add all the numbers in this set:

Then, divide that amount by the total number in the set:

$36491\div 7=5213$

Answer: The mean is 5213.

Compare your answer with the correct one above

Question

Adrienne is trying on dresses for prom. The dresses she likes each cost , , and , respectively. What is the average dress price that Adrienne is considering?

Answer

First, add up all of the dress prices:

Then, divide by the number of dresses:

$522 \div 4=130.50$

Answer: The average dress price is

Compare your answer with the correct one above

Question

Find the average of this set of numbers:

2521, 2512, 2525, 2552, 2551, 2525, 2517

Answer

First, add all the numbers in this set:

Then, divide by the amount of numbers in the set:

$17703\div 7=2529$

Answer: The average is

Compare your answer with the correct one above

Question

In my town, a gallon of milk costs $3.21, $3.39 and $3.51 in three different stores. What is the average price of a gallon of milk in my town?

Answer

First, add all of the prices:

Then divide, that amount by 3 (number of stores in town):

$10.11\div 3=3.37$

Answer: The average price of a gallon of milk is

Compare your answer with the correct one above

Question

In my town, a gallon of gas costs $3.47, $3.79 and $3.60 in three different stations. What is the average price of a gallon of gas in my town?

Answer

First, add all of the prices:

Then, divide by 3 (total number of stations)

$10.88\div 3=3.62$

Answer: The average price for a gallon of gas in my town is

Compare your answer with the correct one above

Question

Find the mean in this set of numbers:

3343, 4434, 4334, 3343, 4343, 3434, 3334

Answer

First, add all the numbers in this set:

Then, divide by 7 (the amount of numbers in this set):

$26565 \div 7=3795$

Answer: The mean is 3795

Compare your answer with the correct one above

Question

While shopping for a couch, Mila found four she really liked. Each cost , , and . What is the average price of a couch Mila is considering?

Answer

First, add all the prices:

Then, divide by 4 (the number of couches):

$2448 \div 4=612$

Answer: The average price of a couch Mila is considering is $612.

Compare your answer with the correct one above

Question

Elizabeth went food shopping today. She spent $32.78, $21.63 and $19.39 at each supermarket. How much did Elizabeth spend, on average, at each supermarket?

Answer

First, add the amounts Elizabeth spent at each supermarket:

Then divide by 3 (the number of supermarkets she went to):

$73.80 \div 3=24.60$

Answer: On average, Elizabeth spent $24.60 at each supermarket.

Compare your answer with the correct one above

Question

Felicia ran three races as a member of the track team. The races were 1000 meters, 2000 meters and 1800 meters, respectively. What was the average distance of the 3 races?

Answer

First, add the lengths of the races:

Then divide by the number of races:

$4800 \div 3=1600$

Answer: The average race was 1600 meters.

Compare your answer with the correct one above

Question

Find the mean for this set of numbers:

6366, 6336, 6366, 6633, 6333, 6363, 6669

Answer

First, add all the numbers in the set:

Then, divide by the total amount of numbers in the set:

$45066\div 7=6438$

Answer: The mean is 6438

Compare your answer with the correct one above

Question

Lori walks her dog for 13 minutes on Monday, 6.5 minutes on Wednesday and 10.5 on Friday. On average, how long are Lori's walks with her dog?

Answer

First, add all the lengths of time:

Then, divide by 3 (the amount of days Lori walked her dog):

$30\div 3=10$

Answer: 10 minutes

Compare your answer with the correct one above

Question

Patricia bought three candles for her home. The candles cost $2.78, $3.68, $1.58, respectively. What was the average price of the candles that Patricia bought?

Answer

First, add all the prices:

Then, divide that amount by 3:

$8.04\div 3=2.68$

Answer: The average price of a candle is $2.68

Compare your answer with the correct one above

Question

Find the mean in this set of numbers:

9078, 9008, 9800, 9099, 9009, 9090, 9008

Answer

First add all the numbers:

Then, divide that number by 7:

$64,092\div 7=9156$

Answer: The mean is 9156

Compare your answer with the correct one above

Question

Find the average of these amounts:

$34.78, $21. 69, $76.89, $47.88

Answer

First, add all the amounts:

Then, divide by 4:

$181.24\div 4=45.31$

Answer: The average is 45.31

Compare your answer with the correct one above

Question

Using the information given in each question, compare the quantity in Column A to the quantity in Column B.

Allie has scored 79, 77, 96, 71, 85, 86, 90, and 84 on her eight science quizzes, and her teacher drops the highest and lowest score.

Column A Column B

Allie's quiz average Allie's quiz average

before the dropped scores after the dropped scores

Answer

Add up the 8 test scores and divide by 8 to figure out the mean (83.5). Now figure out the average between the highest and lowest scores

$\frac{96+71}{2}=83.5$

Since the dropped tests have the same average as the original 8 tests, Allie's score would not change. The correct answer is that the two columns are equal.

Note: If you are good at mental math, here is a quick way to figure out the average of the 8 tests:

First, estimate the average (say, 80). Next, go through the numbers and add or subtract the difference between the number and 80.

79 is 1 below 80.

77 is 3 below 80 (so now we're 4 below 80).

As we continue through the numbers, we get

12 above, 3 above, 8 above, 14 above, 24 above, 28 above.

So the 8 scores are cumulatively 28 above an average score of 80. Now, simply divide 28 by 8 and add this to 80.

Compare your answer with the correct one above

Tap the card to reveal the answer