What is the result of multiplying (3/5) by (5/8)?
- A. 3/8
- B. 3/5
- C. 15/40
- D. 3/30
Correct Answer: A
Rationale: To multiply fractions, multiply the numerators together and the denominators together. For (3/5) * (5/8), you get (3*5) / (5*8) = 15 / 40, which simplifies to 3/8. Therefore, the correct answer is A. Choice B (3/5) is incorrect as it is one of the original fractions being multiplied. Choice C (15/40) is the result of the multiplication but not simplified to its lowest terms. Choice D (3/30) is incorrect as the numerator is not the result of multiplying 3 and 5 together.
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A piece of wood that is 7 1/2 feet long has 3 1/4 feet cut off. How many feet of wood remain?
- A. 4 1/4 feet
- B. 4 1/2 feet
- C. 3 1/2 feet
- D. 3 3/4 feet
Correct Answer: A
Rationale: To find the remaining length of wood, you need to subtract 3 1/4 feet from 7 1/2 feet. When you subtract the fractions, 7 1/2 - 3 1/4, you get 15/2 - 13/4 = 30/4 - 13/4 = 17/4 = 4 1/4 feet. Therefore, the correct answer is 4 1/4 feet. Choice B (4 1/2 feet) is incorrect because the subtraction result is not 1/2. Choice C (3 1/2 feet) is incorrect as it does not match the correct result of 4 1/4 feet. Choice D (3 3/4 feet) is also incorrect as it does not align with the correct answer obtained from the subtraction of fractions.
How many kiloliters are in 147 liters?
- A. 0.147 kiloliters
- B. 1.47 kiloliters
- C. 1,470 kiloliters
- D. 147,000 kiloliters
Correct Answer: A
Rationale: To convert liters to kiloliters, divide by 1000 since there are 1000 liters in a kiloliter. Therefore, 147 liters = 0.147 kiloliters. Choice B is incorrect as it incorrectly moves the decimal point. Choices C and D are significantly larger than the correct answer, indicating an incorrect conversion factor used.
Evaluate the expression -3 x 5.
- A. -15
- B. -2
- C. 2
- D. 15
Correct Answer: A
Rationale: The correct answer is A, which is -15. When you multiply -3 by 5, you get -15. The negative sign in front of the 3 indicates a negative value, and when multiplied by a positive number like 5, the result remains negative. Choices B, C, and D are incorrect because they do not reflect the correct multiplication of -3 and 5.
Apply the polynomial identity to rewrite (a + b)².
- A. a² + b²
- B. 2ab
- C. a² + 2ab + b²
- D. a² - 2ab + b²
Correct Answer: C
Rationale: When you see something like (a + b)², it means you're multiplying (a + b) by itself:
(a + b)² = (a + b) (a + b)
To expand this, we use the distributive property (which says you multiply each term in the first bracket by each term in the second bracket):
Multiply the first term in the first bracket (a) by both terms in the second bracket:
a a = a²
a b = ab
Multiply the second term in the first bracket (b) by both terms in the second bracket:
b a = ab
b b = b²
Now, add up all the results from the multiplication:
a² + ab + ab + b²
Since ab + ab is the same as 2ab, we can simplify it to:
a² + 2ab + b²
So, (a + b)² = a² + 2ab + b².
This is known as a basic polynomial identity, and it shows that when you square a binomial (a two-term expression like a + b), you get three terms: the square of the first term (a²), twice the product of the two terms (2ab), and the square of the second term (b²).
Therefore, the correct answer is C (a² + 2ab + b²)
Half of a circular garden with a radius of 11.5 feet needs weeding. Find the area in square feet that needs weeding. Round to the nearest hundredth. Use 3.14 for π.
- A. 2.4
- B. 207.64
- C. 15.1
- D. 30.1
Correct Answer: B
Rationale: The formula for the area of a full circle is calculated as Area = π (radius²). When finding the area of half a circle, we multiply by 0.5. Thus, the formula becomes Area = 0.5 π (radius²). Given that the radius of the circular garden is 11.5 feet, the calculation using π = 3.14 is as follows: Area = 0.5 3.14 (11.5²) = 0.5 3.14 132.25 = 0.5 415.27 = 207.64 square feet. Therefore, the correct answer is B. Choices A, C, and D are incorrect because they do not reflect the correct calculation for finding the area of half a circular garden with a radius of 11.5 feet.