a dice is rolled what is the probability of getting an even number

HESI A2

HESI A2 Math Practice

1. If a dice is rolled, what is the probability of getting an even number?

A. 16%
B. 33%
C. 66%
D. 50%

Correct answer: D

Rationale: When rolling a standard six-sided die, there are three even numbers (2, 4, 6) out of a total of six possible outcomes (1, 2, 3, 4, 5, 6). The probability of rolling an even number can be calculated as the number of favorable outcomes (3) divided by the total number of outcomes (6), which equals 3/6 = 50%. Therefore, the correct answer is D. Choice A (16%) is incorrect because it does not represent the probability of rolling an even number. Choice B (33%) is incorrect as it does not reflect the correct probability. Choice C (66%) is incorrect as well since it overestimates the probability.

2. If Kevin can wash 30 cars in 15 minutes, how many minutes will it take him to wash 100 cars?

A. 50 minutes
B. 55 minutes
C. 30 minutes
D. 45 minutes

Correct answer: A

Rationale: To find out how many minutes Kevin will take to wash 100 cars, set up a proportion: 30 cars is to 15 minutes as 100 cars is to x minutes. Cross multiplying gives 30x = 1500. Solving for x, x = 1500 / 30 = 50. Therefore, it will take Kevin 50 minutes to wash 100 cars. Choice A is correct. Choice B, C, and D are incorrect as they do not correctly calculate the time needed based on the given information.

3. What is the probability of getting a 1 on a six-sided die?

A. 1/6
B. 1/4
C. 1/3
D. 1/2

Correct answer: A

Rationale: The probability of getting a '1' on a six-sided die is 1 out of 6 possible outcomes, making it a 1/6 probability. Therefore, choice A is correct. Choices B, C, and D are incorrect because they do not represent the correct probability of rolling a '1' on a standard six-sided die.

4. A farmer wants to plant trees around the outside boundaries of his rectangular field with dimensions of 650 meters × 780 meters. Each tree requires 5 meters of free space all around it from the stem. How many trees can he plant?

A. 572
B. 568
C. 286
D. 282

Correct answer: C

Rationale: To determine the number of trees, reduce the field dimensions by 10 meters (5 meters of space on each side). The effective area is 640 meters × 770 meters. Each tree occupies 10 meters × 10 meters. Dividing the effective area by the space for each tree gives: (640 × 770) ÷ (10 × 10) = 286 trees. Choice A, B, and D are incorrect because they do not consider the reduction in field dimensions and the space required for each tree.

5. How many meters are in 3 kilometers?

A. 3000 meters
B. 2000 meters
C. 3500 meters
D. 2500 meters

Correct answer: A

Rationale: The correct answer is A: 3000 meters. To convert kilometers to meters, you need to know that there are 1000 meters in 1 kilometer. Therefore, to find the number of meters in 3 kilometers, you multiply 3 by 1000, resulting in 3000 meters. Choice B, 2000 meters, is incorrect as it doesn't account for the correct conversion factor. Choice C, 3500 meters, and Choice D, 2500 meters, are also incorrect as they provide inaccurate conversions.