SAT Math : SAT Mathematics

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #2981 : Sat Mathematics

Mrs. Hovsepian teaches 5 different math classes. 

The first class contains 42 student. The second class has 38 students. The third class has 67 students. The fourth class has 25 students. The fifth class has 28 students. 

What is the mean number of students per class? 

Possible Answers:

47

43

42

38

40

Correct answer:

40

Explanation:

To get the mean we must add up all of the students and divide by the number of classes. When we add them all up there are 200 total students.

\dpi{100} \small 200\div 5=40

Example Question #31 : Arithmetic Mean

Find the arithmetic mean of the following set of numbers:

\dpi{100} \small 6,8,12,16,18

Possible Answers:

\dpi{100} \small 16

\dpi{100} \small 8

\dpi{100} \small 6

\dpi{100} \small 18

\dpi{100} \small 12

Correct answer:

\dpi{100} \small 12

Explanation:

The mean is adding all the numbers then dividing by the number of items.

In this case we have, \dpi{100} \small x-b,x-y,x,x+b,x+y

where \dpi{100} \small x=12, b= 6, y = 4

When this happens, the average is \dpi{100} \small x

Example Question #61 : Data Analysis

 

Possible Answers:

Correct answer:

Explanation:

Arithmetic mean:        given: 

Solve:  

                      

                           

                               

Example Question #31 : How To Find Arithmetic Mean

A class consists of 10 students. The teacher wrote the test and expects the class to have an average score of at least 80. The average score of 9 people was calculated and it was 78. What score does the last person have to get in order to reach the teacher's standard?

Possible Answers:

94

82

88

100

98

Correct answer:

98

Explanation:

The total score of those 9 students is 9\cdot 78=702.

The standard score for the entire class was 10\cdot 80=800.

Therefore, the last person needs a score of 800-702=98.

Example Question #2981 : Sat Mathematics

What is the average (mean) of

Possible Answers:

Correct answer:

Explanation:

By adding all of the expressions we get  

which averages to ,

which will simplify to .

Example Question #2981 : Sat Mathematics

The mean of a series of 6 numbers (11, 12, 14, 17, 18, x) is 15. Solve for x.

Possible Answers:

18

19

17

16

Correct answer:

18

Explanation:

If the mean of 6 numbers is 15, that implies that the sum of the numbers is equal to 90 (6 x 15).

Therefore, \small 90=(11+12+14+17+18+x) or \small 90=(72+x) \small 90-72=x=18

Example Question #2982 : Sat Mathematics

A police officer walked into a room full of suspects and turn out their pockets.  The chart below shows the number of coins each man had.

Screen_shot_2013-09-04_at_10.20.59_am

The police claim the man with the amount of money closest to the arithmetic mean of the group is guilty.  Who is it?

Possible Answers:

Suspect 4

Suspect 3

Suspect 2

Suspect 6

Suspect 1

Correct answer:

Suspect 2

Explanation:

Screen_shot_2013-09-04_at_10.26.20_am

Summing total money and dividing by the number of suspects gives us an average of approximately $2.73.  By comparing it to the amounts held by the suspects, we can see that Suspect #2 is guilty.

Example Question #2983 : Sat Mathematics

The average temperature for 6 days in July is 87^\circ F. If on the seventh day, the temperature is 54^\circ F, what is the average temperature over those seven days?

Possible Answers:

There is not enough information to answer this question.

82.3^\circ F

76.0^\circ F

70.5^\circ F

None of the available answers.

Correct answer:

82.3^\circ F

Explanation:

In order to calculate mean, we can act as though the temperature was exactly 87^\circ F for the first six days and 54^\circ F on the seventh day. The mean can be expressed:

\frac{(6\times 87)+54}{7}=\frac{522+54}{7}=\frac{576}{7}\approx 82.3^\circ F

Example Question #2984 : Sat Mathematics

 

If the average  of  b + 2 is equal to the average of b + 4 + 6. What is the value of b ?

Possible Answers:

20

8

14

10

16

Correct answer:

14

Explanation:

\frac{b+2}{2}=\frac{b+4+6}{3}

3b+6=2b+8+12

b=14

Example Question #32 : How To Find Arithmetic Mean

The test average for a class of 13 students is 87%. If two students take make-up tests the next day and score 97% and 56% respectively, what is the new average?

Possible Answers:

The average does not change

Correct answer:

Explanation:

In order to calculate the new average, we can act as though each of the thirteen students who originally took the test each earned 87%:

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