Nokea
What is the result of adding 7/21 + 10/21?
- A. 17/21
- B. 15/21
- C. 9/21
- D. 10/21
Correct Answer: A
Rationale: When adding fractions with the same denominator, you simply add the numerators while keeping the denominator the same. In this case, 7/21 + 10/21 = 17/21. Therefore, the correct answer is A. Choice B (15/21) is incorrect because it adds the numerators incorrectly. Choice C (9/21) is incorrect as it does not reflect the sum of the fractions provided. Choice D (10/21) is also incorrect as it does not represent the correct sum of the two fractions.
You may also like to solve these questions
Ratio and proportion 1.2:x=14:42.
- A. 2
- C. 1
- D. 3
Correct Answer: D
Rationale: Cross-multiply to solve for
x
x:
1.2
42
=
14
x
1.242=14x
50.4
=
14
x
50.4=14x
x
=
50.4
14
=
3.6
x=
14
50.4
​
=3.6
Which of the following percentages is equal to 0.45?
- A. 4.5%
- B. 0.045%
- C. 0.45%
- D. 45%
Correct Answer: D
Rationale: To convert 0.45 to a percentage, you multiply by 100: 0.45 100 = 45%. Therefore, the correct answer is D. 45%.
Choice A, 4.5%, is incorrect. This percentage would be equal to 0.045, not 0.45. Choice B, 0.045%, is also incorrect. It represents 0.045, not 0.45. Choice C, 0.45%, is very close to the correct answer but actually represents 0.0045, not 0.45.
If a student earns $120 for a 10-hour tutoring session and works 6 hours, how much did the student earn?
- A. $72
- B. $90
- C. $80
- D. $50
Correct Answer: A
Rationale: To find the amount earned for 6 hours of work, calculate the hourly rate by dividing the total earnings ($120) by the total hours worked (10 hours): $120 · 10 = $12 per hour. Then, multiply the hourly rate by the number of hours worked (6): $12 6 = $72. Therefore, the student earned $72 for working 6 hours. Choice B ($90) is incorrect because it miscalculates the hourly rate. Choice C ($80) is incorrect as it does not consider the correct hourly rate. Choice D ($50) is incorrect as it calculates the earnings based on the wrong hourly rate.
Scientific notation is a way to represent very large or small numbers in a compact form. If a number is written as 4.82 x 10^3, what is the value of the number in standard form?
- A. 0.004 82
- B. 0.482
- C. 4820
- D. 4820000
Correct Answer: C
Rationale: Rationale:
When a number is written in scientific notation as \(a \times 10^n\), the value of the number in standard form is obtained by multiplying \(a\) by \(10^n\). In this case, the number is \(4.82 \times 10^3\). To convert this to standard form, we multiply 4.82 by \(10^3\), which means moving the decimal point 3 places to the right.
\(4.82 \times 10^3 = 4820\)
Therefore, the value of the number in standard form is 4820, which corresponds to option C.
Sally eats 3/5 of her lunch. John eats 75%. Who ate more?
- A. John
- B. Sally
- C. Both the same
- D. Neither
Correct Answer: A
Rationale: To compare, convert both to decimals or percentages:
Sally ate 3/5, which is 0.6 or 60%. John ate 75%. Since 75% is greater than 60%, John ate more than Sally. Thus, the correct answer is A. John. Choice B is incorrect because Sally ate a smaller percentage of her lunch compared to John. Choice C is incorrect as the percentages consumed are different. Choice D is incorrect as one of them ate more.