1.
What is the probability that a month picked at random starts with the letter J?
Correct Answer
B. 1/4
Explanation
The probability that a month picked at random starts with the letter J is 1/4. This is because out of the twelve months in a year, only January, June, and July start with the letter J. Therefore, the probability is 3 out of 12, which simplifies to 1/4.
2.
What is the probability that a day of the week picked at random is a Saturday?
Correct Answer
D. 1/7
Explanation
The probability of picking a Saturday at random out of a week is 1 out of 7, because there are 7 days in a week and only 1 of those days is a Saturday.
3.
A card game has 25 red cards, 25 green cards, 25 yellow cards, 25 blue cards, and 8 wild cards. What is the probability that the first card dealt is a wild card?
Correct Answer
C. 2/27
Explanation
The probability of drawing a wild card as the first card dealt can be calculated by dividing the number of wild cards (8) by the total number of cards in the deck (100). This gives us a probability of 8/100, which can be simplified to 2/25. However, since the question asks for the probability in terms of the whole deck (including the wild cards), we need to add the 8 wild cards to the total number of cards, giving us a new total of 108 cards. The probability of drawing a wild card as the first card dealt from this new deck is 8/108, which simplifies to 2/27.
4.
A weather reporter says that there is a 40% chance of rain. What is the probability of no rain.
Correct Answer
A. 60%
Explanation
The probability of no rain can be calculated by subtracting the probability of rain from 100%. Since the weather reporter says there is a 40% chance of rain, the probability of no rain would be 100% - 40% = 60%.
5.
A spinner that is numbered 1-7 is used for a game. What is the probability that a 5 will be spun?
Correct Answer
C. 1/7
Explanation
The spinner has a total of 7 numbers, so there is a total of 7 possible outcomes. Since there is only one 5 on the spinner, the probability of spinning a 5 is 1 out of the 7 possible outcomes, which can be simplified to 1/7.
6.
A spinner that is numbered 1-7 is used in a game. What is the probability that an 8 will be spun?
Correct Answer
B. 0%
Explanation
The spinner is numbered from 1 to 7, so it is not possible for an 8 to be spun. Therefore, the probability of spinning an 8 is 0%.
7.
A spinner that is numbered 1-7 is used in a game. What is the probability that an 8 will not be spun?
Correct Answer
A. 100%
Explanation
The probability that an 8 will not be spun is 100% because the spinner only has numbers from 1 to 7. Since there is no 8 on the spinner, it is impossible for an 8 to be spun. Therefore, the probability of not spinning an 8 is certain, or 100%.
8.
A bag contains 4 red, 5 black, 6 green, and 10 yellow jelly beans. A student selects one jelly bean at random. What is the probability that a yellow jelly bean will be selected?
Correct Answer
D. 2/5
Explanation
The probability of selecting a yellow jelly bean can be calculated by dividing the number of yellow jelly beans by the total number of jelly beans in the bag. In this case, there are 10 yellow jelly beans out of a total of 25 jelly beans. Therefore, the probability of selecting a yellow jelly bean is 10/25, which simplifies to 2/5.
9.
What is the probability that a month picked at random ends in y?
Correct Answer
C. 1/3
Explanation
The probability that a month picked at random ends in "y" is 1/3. There are 12 months in a year, and only 4 of them (January, February, July, and December) end in "y". Therefore, the probability is 4/12, which simplifies to 1/3.
10.
If a month is picked at random, what is the probability that the month will start with M?
Correct Answer
B. 1/6
Explanation
The probability that a month will start with M is 1 out of 6, since there are 12 months in a year and only one of them starts with the letter M (March).
11.
A box of a dozen donuts has 3 lemon cream-filled, 5 chocolate cream-filled, and 4 vanilla cream-filled. If the donuts look identical, what is the probability of picking a lemon cream-filled?
Correct Answer
B. 1/4
Explanation
The probability of picking a lemon cream-filled donut can be found by dividing the number of lemon cream-filled donuts by the total number of donuts in the box. There are 3 lemon cream-filled donuts out of a total of 12 donuts in the box. Therefore, the probability is 3/12, which simplifies to 1/4.
12.
There are 24 candy-coated chocolate pieces in a bag. Eight have defects in the coating that can be seen only with close inspection. What is the probability of pulling out a defective piece without looking?
Correct Answer
D. 1/3
Explanation
The probability of pulling out a defective piece without looking can be determined by dividing the number of defective pieces by the total number of candy-coated chocolate pieces in the bag. In this case, there are 8 defective pieces out of a total of 24 candy-coated chocolate pieces. Therefore, the probability is 8/24, which simplifies to 1/3.
13.
For his garden, Clay has a mixture of 12 white corn seeds, 24 yellow corn seeds, and 16 bi-color corn seeds. If he reaches for a seed without looking, what is the probability that Clay will plant a bi-color corn seed first?
Correct Answer
A. 4/13
Explanation
Clay has a total of 12 + 24 + 16 = 52 corn seeds. Out of these, there are 16 bi-color corn seeds. Therefore, the probability of Clay planting a bi-color corn seed first is 16/52, which simplifies to 4/13.
14.
Seven sisters have to choose which day each will wash the dishes. They put equal size pieces of paper, each labeled with a day of the week in a hat. What is the probability that the first sister who draws will choose a weekend day?
Correct Answer
D. 1/7
Explanation
The probability that the first sister will choose a weekend day can be determined by counting the number of weekend days (2) out of the total number of days (7) and then dividing it by the total number of days. Therefore, the probability is 2/7.
15.
A computer chooses a number between 1-50 at random. What is the probability that the number chosen is an odd number?
Correct Answer
C. 1/2
Explanation
The probability of choosing an odd number is equal to the ratio of the number of odd numbers to the total number of numbers. In this case, there are 25 odd numbers (1, 3, 5, ... 49) and 50 total numbers (1-50). Therefore, the probability of choosing an odd number is 25/50, which simplifies to 1/2.
16.
A computer chooses a number between 1-50 at random. What is the probability that the number chosen will be a 2-digit number?
Correct Answer
D. 41/50
Explanation
The probability of choosing a 2-digit number can be found by dividing the number of 2-digit numbers (which is 90) by the total number of possible numbers (which is 50). Therefore, the probability is 90/50, which simplifies to 9/5. However, since probabilities must be between 0 and 1, the answer is not 9/5. Therefore, the correct answer is 41/50.