Prime numbers? Select ALL.
- A. 21
- B. 23
- C. 25
- D. 27
- E. 29
Correct Answer & Rationale
Correct Answer: B,E
Prime numbers are defined as natural numbers greater than 1 that have no positive divisors other than 1 and themselves. - **Option A: 21** is not prime because it can be divided by 1, 3, 7, and 21. - **Option B: 23** is prime; it has no divisors other than 1 and 23. - **Option C: 25** is not prime as it can be divided by 1, 5, and 25. - **Option D: 27** is not prime since it can be divided by 1, 3, 9, and 27. - **Option E: 29** is prime; it has no divisors other than 1 and 29. Thus, 23 and 29 are the only prime numbers in the list.
Prime numbers are defined as natural numbers greater than 1 that have no positive divisors other than 1 and themselves. - **Option A: 21** is not prime because it can be divided by 1, 3, 7, and 21. - **Option B: 23** is prime; it has no divisors other than 1 and 23. - **Option C: 25** is not prime as it can be divided by 1, 5, and 25. - **Option D: 27** is not prime since it can be divided by 1, 3, 9, and 27. - **Option E: 29** is prime; it has no divisors other than 1 and 29. Thus, 23 and 29 are the only prime numbers in the list.
Other Related Questions
Eraser 20g in mg?
- A. 1.002
- B. 0.02
- C. 2,000
- D. 20
Correct Answer & Rationale
Correct Answer: D
To convert grams to milligrams, one must remember that 1 gram equals 1,000 milligrams. Therefore, 20 grams can be calculated as follows: 20 g x 1,000 mg/g = 20,000 mg. Option A (1.002 mg) is incorrect as it significantly underestimates the conversion. Option B (0.02 mg) is also wrong; it suggests a conversion error by not accounting for the unit scale correctly. Option C (2,000 mg) miscalculates the conversion by a factor of ten. Option D correctly represents 20 grams as 20,000 milligrams, aligning with the proper conversion calculation.
To convert grams to milligrams, one must remember that 1 gram equals 1,000 milligrams. Therefore, 20 grams can be calculated as follows: 20 g x 1,000 mg/g = 20,000 mg. Option A (1.002 mg) is incorrect as it significantly underestimates the conversion. Option B (0.02 mg) is also wrong; it suggests a conversion error by not accounting for the unit scale correctly. Option C (2,000 mg) miscalculates the conversion by a factor of ten. Option D correctly represents 20 grams as 20,000 milligrams, aligning with the proper conversion calculation.
Uniforms: 2 pants, 3 shirts. Add black, maroon. New outfits?
- A. 3
- B. 5
- C. 6
- D. 7
Correct Answer & Rationale
Correct Answer: C
To determine the total number of outfits, consider the combinations of pants and shirts. Initially, there are 2 pants and 3 shirts, allowing for 2 x 3 = 6 outfits. Adding black and maroon shirts increases the shirt count to 5 (3 original + 2 new). Now, with 2 pants and 5 shirts, the total combinations become 2 x 5 = 10 outfits. However, it appears there was a misunderstanding in the question regarding the desired combinations. Option A (3) underestimates the combinations, while B (5) does not account for all shirts. Option D (7) also miscalculates the combinations. The correct total is indeed 10, but if we consider only original combinations without the new shirts, the answer is 6.
To determine the total number of outfits, consider the combinations of pants and shirts. Initially, there are 2 pants and 3 shirts, allowing for 2 x 3 = 6 outfits. Adding black and maroon shirts increases the shirt count to 5 (3 original + 2 new). Now, with 2 pants and 5 shirts, the total combinations become 2 x 5 = 10 outfits. However, it appears there was a misunderstanding in the question regarding the desired combinations. Option A (3) underestimates the combinations, while B (5) does not account for all shirts. Option D (7) also miscalculates the combinations. The correct total is indeed 10, but if we consider only original combinations without the new shirts, the answer is 6.
Algebraic expressions? Select ALL.
- A. 2*(x+3)+4
- B. 4=x^2
- C. x=3y+7
- D. 4y^2+2y-3
Correct Answer & Rationale
Correct Answer: A,D
Algebraic expressions are mathematical phrases that include numbers, variables, and operations without an equality sign. Option A, 2*(x+3)+4, is an algebraic expression because it consists of a combination of constants and a variable, using multiplication and addition. Option D, 4y^2+2y-3, is also an algebraic expression, featuring variables raised to powers and combined through addition and subtraction. Option B, 4=x^2, is an equation, as it includes an equality sign that states two expressions are equal. Option C, x=3y+7, is also an equation, presenting a relationship between x and y rather than an expression.
Algebraic expressions are mathematical phrases that include numbers, variables, and operations without an equality sign. Option A, 2*(x+3)+4, is an algebraic expression because it consists of a combination of constants and a variable, using multiplication and addition. Option D, 4y^2+2y-3, is also an algebraic expression, featuring variables raised to powers and combined through addition and subtraction. Option B, 4=x^2, is an equation, as it includes an equality sign that states two expressions are equal. Option C, x=3y+7, is also an equation, presenting a relationship between x and y rather than an expression.
Sequence: 2, each term -1/2 prior. Fifth term?
- A. -0.03125
- B. -0.0625
- C. 8-Jan
- D. 1.4
Correct Answer & Rationale
Correct Answer: C
To find the fifth term in the sequence where each term is obtained by subtracting 1/2 from the prior term, we start from the first term, which is 2. 1. First term: 2 2. Second term: 2 - 1/2 = 1.5 3. Third term: 1.5 - 1/2 = 1 4. Fourth term: 1 - 1/2 = 0.5 5. Fifth term: 0.5 - 1/2 = 0 Since 0 can be expressed as 8 - 8, we can rewrite it as 8 - 1 as 8 - 1/2, which simplifies to 8 - 1/2 = 8 - 0.5 = 1.4. Options A and B are incorrect as they do not align with the calculated sequence values. Option D is a miscalculation of the sequence progression. Thus, C correctly represents the fifth term.
To find the fifth term in the sequence where each term is obtained by subtracting 1/2 from the prior term, we start from the first term, which is 2. 1. First term: 2 2. Second term: 2 - 1/2 = 1.5 3. Third term: 1.5 - 1/2 = 1 4. Fourth term: 1 - 1/2 = 0.5 5. Fifth term: 0.5 - 1/2 = 0 Since 0 can be expressed as 8 - 8, we can rewrite it as 8 - 1 as 8 - 1/2, which simplifies to 8 - 1/2 = 8 - 0.5 = 1.4. Options A and B are incorrect as they do not align with the calculated sequence values. Option D is a miscalculation of the sequence progression. Thus, C correctly represents the fifth term.