ACT Math : Data Analysis

Study concepts, example questions & explanations for ACT Math

varsity tutors app store varsity tutors android store varsity tutors ibooks store

Example Questions

Example Question #3 : How To Find Range

The following is a list of the amount of students in each of five 3rd grad classrooms:
23, 27, 19, 31, 33. What is the range of the number of students in each classroom?

Possible Answers:

Correct answer:

Explanation:

The range is the highest minus the lowest value in a given data set contains. Thus the low end of the range is the low number, or 19 students, and the high end of the range is the high number, or 33.

Subtracting the lowest value from the highest we get,

.

Therefore the range of the data set is .

Example Question #1 : How To Find Range

Find the range of the following set of numbers.

Possible Answers:

Correct answer:

Explanation:

To find range, simply subtract the smallest number from the largest number. Thus,

Example Question #2 : How To Find Range

Find the range of the following set of numbers:

Possible Answers:

Correct answer:

Explanation:

To find the range, simply take the difference of the smallest and largest numbers. 

The largest number is,  and the smallest number is .

 Thus,

.

Example Question #3 : How To Find Range

Find the range of the following set of numbers:

Possible Answers:

Correct answer:

Explanation:

To find range, simply subract the smallest number from the largest. Thus,

Example Question #1 : How To Find The Probability Of An Outcome

If two regular six-sided dice are rolled at the same time, what is the probability that the sum of the their numbers will be prime?

 

Possible Answers:

5/12

1/2

7/18

1/4

Correct answer:

5/12

Explanation:

There number of possible outcomes is equal to six times six, or thirty-six. The sum of the two dice must be either 2, 3, 5, 7, or 11. There are 15 out of the 36 outcomes that would result in a sum that is a prime number:

[1,1], [1,2], [1,4], [1,6], [2,1], [2,3], [2,5], [3,2], [3,4], [4,1], [4,3], [5,2], [5,6], [6,1], [6,5]

 

 

Example Question #1 : Probability

Maria is planning the seating for the head table at a college gala. There are eight speakers that will be seated along one side of the table. Richard wants to sit beside Hang, and Maria knows that Thomas and Lily should not be seated together. In how many ways can Maria make up the seating plan? 

 
Possible Answers:
3975
10080
7200
8100
2880
Correct answer: 7200
Explanation:

The simplest way to solve this is to find the number of seating arrangements in which Richard and Hang are seated together and then subtract those in which Thomas and Lily are also seated together. Consider Richard and Hang as a unit. This pair can be arranged with the other six speakers in 7P7 ways. For each of these ways, Hang could be either on Richard’s left or his right. Thus, there are 7P7 × 2 = 10 080 arrangements in which Richard and Hang are seated together. Now also consider Lily and Thomas as a unit. The two pairs can be arranged with the remaining four speakers in 6P6 ways, and the total number of arrangements with each of the pairs together is 6P6 × 2 × 2 = 2880.

Therefore, the number of seating arrangements in which Richard and Hang are adjacent but Thomas and Lily are not is 10 080  2880 = 7 200.

 

Example Question #1 : How To Find The Probability Of An Outcome

{10, 12, 24, 50, 60, 100, 260, 480, 606, 1000}

What is the probability that a number selected randomly from the set will be divisible by both 4 and 6? 

Possible Answers:

1/10

2/5

3/10

1/2

3/5

Correct answer:

2/5

Explanation:

First, find the numbers that in the set that are divisible by 4. 12, 24, 60, 100, 260, 480, and 1000 are all divisible by 4. Now find the numbers that are divisible by 6. 12, 24, 60, 480, 606 are all divisible by 6. The numbers that are divisible by both 4 and 6 are 12, 24, 60, and 480, or 4 total numbers from the set. So 4 out of the 10 numbers are divisible by 4 and 6.  The probablility is 4/10, which reduces to 2/5.  The correct answer is 2/5.

Example Question #2 : Probability

Jacob was 27 years old when his son Mike was born. Mike was 23 years old when his son Sam was born. Sam will celebrate his seventh birthday in 2014. What year was Jacob born?

Possible Answers:

2007

1987

1964

1984

1957

Correct answer:

1957

Explanation:

If Sam will celebrate his seventh birthday in 2014, then he was born in 2007. So Mike was born 23 years before in 1984 and Jacob was born 27 years before that in 1957.

If you answered 1964, then you did not factor that Sam was 7 years old at the time of calculation.

If you answered 1984, then you found the year that Mike was born, not Jacob.

If you answered 2007, then you found the year that Sam was born, not Jacob.

If you answered 1987, then you just subtracted 27 years old from the day of the party in 2014.

Example Question #1 : Probability

What is the probability of choosing two consecutive red cards from a standard deck of cards, if replacement is not allowed?

Possible Answers:

51/100

61/204

17/25

25/102

23/25

Correct answer:

25/102

Explanation:

Probability = what you want ÷ total number

A standard deck of playing cards has 52 cards, with 4 suits and 13 cards in each suit

Choosing two red cards = 26 * 25 = 650

Choosing two cards = 52 * 51 = 2652

So the probabiulity of choosing 2 red cards is 650/2652 = 25/102

If replacement is allowed, then the probability of choosing 2 red cards becomes 676/2704 = 1/4

Example Question #2 : How To Find The Probability Of An Outcome

If x percent of 300 is 120, what is 175% of x?

Possible Answers:

320

310

70

50

Correct answer:

70

Explanation:

120 is 40% of 300, so x = 40.

175% of 40 is equal to 70.

Learning Tools by Varsity Tutors