ACT Math : Data Analysis

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #27 : Probability

Robert has a lot of loose change in his pocket. He pulled it all out and found that he had 5 nickels, 8 dimes, 3 quarters, and 13 pennies in his pocket. Robert then put all the change back in his pocket except for the quarters. What is the probability of Robert pulling out a dime at random? (assume that the physical size of the coins has no effect on their probability of being picked)

Possible Answers:

1/13

4/13

13/26

1/26

8/29

Correct answer:

4/13

Explanation:

The total number of coins in Robert's pocket is 26. because there are 8 dimes, he has an 8/26 chance of choosing a dime. This reduces down to 4/13 when you divide the numerator and denominator by 2 (GCF)

Example Question #141 : Data Analysis

If there are 490 marbles in a bag, divided evenly into the seven colors of the rainbow, what is the probability of picking out a marble that is one of the three primary colors?

Possible Answers:

Correct answer:

Explanation:

Since the rainbow consists of seven colors, and there are 490 marble, there are 70 of each color (490/7 = 70).

The probability of choosing a marble that is a primary color would be (70 * 3)/490 = 210/490 = 3/7.

Example Question #142 : Data Analysis

A bottle contains 7 yellow jelly beans, 8 blue jelly beans, 9 green jelly beans, and 14 purple jelly beans. If you select one jelly bean at random, what is the probability that it is neither purple nor yellow?  Round to the nearest hundredth.

Possible Answers:

0.45

0.76

0.57

0.43

0.87

Correct answer:

0.45

Explanation:

This is a probability question. There are 17 jelly beans that could be selected to satisfy the conditions of selecting a jelly bean that is neither purple or yellow. There are 38 total jelly beans. The proportion should be set up as 17/38 or 0.45, because this represents the probability that a jelly bean that is not purple or yellow will be selected.

Example Question #143 : Data Analysis

What is the probability of rolling a sum of four or less on a pair of regular six-sided dice?

Possible Answers:

1/2

1/6

1/4

1/12

1/3

Correct answer:

1/6

Explanation:

Probability = what you want ÷ total number

There are 6 ways to get a sum of four or less:  (1, 1), (1, 2), (1, 3), (2, 1), (2, 2), (3, 1)

The total would be 6 * 6 = 36

So the probability of getting four or less (4, 3, 2, 1) is 6/36 = 1/6

The probability of getting less than four (3, 2, 1) is 3/36 = 1/12

Example Question #31 : How To Find The Probability Of An Outcome

If you flip a coin 3 times, what are the odds that the coin will be heads all three times?

Possible Answers:

Correct answer:

Explanation:

If you flip a coin, the chances of you getting heads is 1/2. This is true every time you flip the coin so if you flip it 3 times, the chances of you getting heads every time is 1/2 * 1/2 * 1/2, or 1/8.

Example Question #31 : How To Find The Probability Of An Outcome

What is the probability of getting a sum of four when rolling two six-sided dice?

Possible Answers:

Correct answer:

Explanation:

The sample space for rolling two six-sided dice , since each die has sides.

There are three ways to roll a four.

The probability of rolling a four is given by the number of outcomes that produce a four divided by the total number of outcomes.

Example Question #31 : Probability

A bag contains 3 green marbles, 5 red marbles, and 9 blue marbles.

What is the probability of drawing a red marble?

Possible Answers:

Correct answer:

Explanation:

The probability of drawing a red marble is \dpi{100} \small \frac{5}{17}.

The total number of marbles \dpi{100} \small (3+5+9) is \dpi{100} \small 17, so there are \dpi{100} \small 17 possible outcomes. \dpi{100} \small 5 of these possible outcomes are red marbles, so the probability of a red marble out of any marble is \dpi{100} \small \frac{5}{17}.

Example Question #31 : How To Find The Probability Of An Outcome

In a certain lottery, ten balls are numbered #1 through #10.  Two winning balls will be drawn without replacement.

Billy plays the lottery and picks the numbers 9 and 10.

 

What is the probability Billy Bob will have two winning numbers?

Possible Answers:

1/90

1/50

1/100

1/45

2/95

Correct answer:

1/90

Explanation:

(1/10)(1/9) = 1/90

Example Question #31 : How To Find The Probability Of An Outcome

In a lottery, ten balls are numbered #1 through #10.  Two winning balls will be drawn without replacement.

Billy plays the lottery and picks the numbers 9 and 10.

 

What is the probability that Billy has no winning numbers? (Round to the nearest one percent.)

Possible Answers:

88%

92%

55%

96%

62%

Correct answer:

62%

Explanation:

The correct answer is 62%, obtained from (8/10) (7/9) = 0.62222

Example Question #31 : How To Find The Probability Of An Outcome

A fair coin is tossed 2 times.

When flipping a coin twice, what is the probability of getting one heads and one tails? Without regard to order. I.e., either the heads or the tails could appear first.

Possible Answers:

1.0

0.75

0

0.5

0.25

Correct answer:

0.5

Explanation:

There are 4 possible outcomes for the event {HH, HT, TH, TT}. Two of these four outcomes include exactly one heads and one tails. 

Thus the solution is 2/4 = 1/2 = 0.5

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