two thirds of the students in mr garcias class are boys if there are 27 students in the class how many of them are girls

HESI A2

Practice HESI A2 Math Test

1. In Mr. Garcia's class, two-thirds of the students are boys. If there are 27 students in the class, how many of them are girls?

A. 1
B. 9
C. 12
D. 20

Correct answer: B

Rationale: If two-thirds of the students are boys, then one-third of the students must be girls. One-third of 27 is 9, so there are 9 girls in Mr. Garcia's class. Therefore, the correct answer is 9. Choice A is incorrect because it is too low; only one-third of the students are girls. Choices C and D are incorrect as they do not reflect the correct calculation based on the given information in the question.

2. Multiply: 54 × 45. Express the result in decimal form.

A. 0.0243
B. 0.243
C. 2.43
D. 24.3

Correct answer: D

Rationale: To multiply 54 by 45, you should multiply the two numbers together: 54 x 45 = 2430. The decimal point is placed after counting the total decimal places in the numbers being multiplied. As there are no decimal places in the numbers 54 and 45, the result is 2430, which is correctly expressed as 24.3 when considering the decimal point placement. Choice A (0.0243) and Choice B (0.243) are incorrect as they represent fractions of 2430. Choice C (2.43) is incorrect as it incorrectly places the decimal point one place before the actual result.

3. Express the ratio of 25:80 as a percentage.

A. 31.25%
B. 34%
C. 41.25%
D. 43.75%

Correct answer: A

Rationale: To express the ratio 25:80 as a percentage, follow these steps: First, divide 25 by 80: 25/80 = 0.3125. Then, multiply by 100 to convert to a percentage: 0.3125 × 100 = 31.25%. Therefore, the ratio 25:80 is equivalent to 31.25%. Choice A is correct. Choice B (34%) is incorrect because it does not accurately represent the ratio 25:80. Choice C (41.25%) and Choice D (43.75%) are also incorrect as they do not match the calculated percentage for the given ratio.

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. What is the greatest common factor (GCF) of 12 and 18?

A. 2
B. 3
C. 6
D. 9

Correct answer: C

Rationale: The greatest common factor (GCF) of two numbers is the largest number that divides both numbers without leaving a remainder. To find the GCF of 12 and 18, we factorize each number: 12 = 2 x 2 x 3 and 18 = 2 x 3 x 3. The common factors are 2 and 3. The GCF is the product of these common factors, which is 6. Therefore, 6 is the greatest common factor of 12 and 18. Choice A (2) and Choice B (3) are factors of both numbers but not the greatest common factor. Choice D (9) is not a factor of both 12 and 18, making it incorrect.