| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.96 |
| Score | 0% | 59% |
If \(\left|a\right| = 7\), which of the following best describes a?
a = -7 |
|
a = 7 |
|
a = 7 or a = -7 |
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none of these is correct |
The absolute value is the positive magnitude of a particular number or variable and is indicated by two vertical lines: \(\left|-5\right| = 5\). In the case of a variable absolute value (\(\left|a\right| = 5\)) the value of a can be either positive or negative (a = -5 or a = 5).
A circular logo is enlarged to fit the lid of a jar. The new diameter is 75% larger than the original. By what percentage has the area of the logo increased?
| 37\(\frac{1}{2}\)% | |
| 20% | |
| 25% | |
| 22\(\frac{1}{2}\)% |
The area of a circle is given by the formula A = πr2 where r is the radius of the circle. The radius of a circle is its diameter divided by two so A = π(\( \frac{d}{2} \))2. If the diameter of the logo increases by 75% the radius (and, consequently, the total area) increases by \( \frac{75\text{%}}{2} \) = 37\(\frac{1}{2}\)%
What is \( \frac{2}{6} \) ÷ \( \frac{2}{8} \)?
| \(\frac{1}{20}\) | |
| \(\frac{4}{21}\) | |
| 1\(\frac{1}{3}\) | |
| \(\frac{8}{81}\) |
To divide fractions, invert the second fraction and then multiply:
\( \frac{2}{6} \) ÷ \( \frac{2}{8} \) = \( \frac{2}{6} \) x \( \frac{8}{2} \)
To multiply fractions, multiply the numerators together and then multiply the denominators together:
\( \frac{2}{6} \) x \( \frac{8}{2} \) = \( \frac{2 x 8}{6 x 2} \) = \( \frac{16}{12} \) = 1\(\frac{1}{3}\)
Roger loaned Charlie $400 at an annual interest rate of 7%. If no payments are made, what is the interest owed on this loan at the end of the first year?
| $4 | |
| $28 | |
| $14 | |
| $30 |
The yearly interest charged on this loan is the annual interest rate multiplied by the amount borrowed:
interest = annual interest rate x loan amount
i = (\( \frac{6}{100} \)) x $400
i = 0.07 x $400
i = $28
What is \( 2 \)\( \sqrt{12} \) + \( 9 \)\( \sqrt{3} \)
| 11\( \sqrt{4} \) | |
| 13\( \sqrt{3} \) | |
| 18\( \sqrt{3} \) | |
| 11\( \sqrt{3} \) |
To add these radicals together their radicands must be the same:
2\( \sqrt{12} \) + 9\( \sqrt{3} \)
2\( \sqrt{4 \times 3} \) + 9\( \sqrt{3} \)
2\( \sqrt{2^2 \times 3} \) + 9\( \sqrt{3} \)
(2)(2)\( \sqrt{3} \) + 9\( \sqrt{3} \)
4\( \sqrt{3} \) + 9\( \sqrt{3} \)
Now that the radicands are identical, you can add them together:
4\( \sqrt{3} \) + 9\( \sqrt{3} \)