| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.86 |
| Score | 0% | 57% |
What is \( \frac{2}{3} \) - \( \frac{3}{7} \)?
| \(\frac{5}{21}\) | |
| 1 \( \frac{3}{10} \) | |
| \( \frac{8}{21} \) | |
| \( \frac{4}{11} \) |
To subtract these fractions, first find the lowest common multiple of their denominators. The first few multiples of 3 are [3, 6, 9, 12, 15, 18, 21, 24, 27, 30] and the first few multiples of 7 are [7, 14, 21, 28, 35, 42, 49, 56, 63, 70]. The first few multiples they share are [21, 42, 63, 84] making 21 the smallest multiple 3 and 7 share.
Next, convert the fractions so each denominator equals the lowest common multiple:
\( \frac{2 x 7}{3 x 7} \) - \( \frac{3 x 3}{7 x 3} \)
\( \frac{14}{21} \) - \( \frac{9}{21} \)
Now, because the fractions share a common denominator, you can subtract them:
\( \frac{14 - 9}{21} \) = \( \frac{5}{21} \) = \(\frac{5}{21}\)
A circular logo is enlarged to fit the lid of a jar. The new diameter is 55% larger than the original. By what percentage has the area of the logo increased?
| 27\(\frac{1}{2}\)% | |
| 15% | |
| 37\(\frac{1}{2}\)% | |
| 20% |
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 55% the radius (and, consequently, the total area) increases by \( \frac{55\text{%}}{2} \) = 27\(\frac{1}{2}\)%
What is \( \frac{10\sqrt{21}}{2\sqrt{7}} \)?
| 5 \( \sqrt{\frac{1}{3}} \) | |
| 5 \( \sqrt{3} \) | |
| 3 \( \sqrt{5} \) | |
| \(\frac{1}{3}\) \( \sqrt{\frac{1}{5}} \) |
To divide terms with radicals, divide the coefficients and radicands separately:
\( \frac{10\sqrt{21}}{2\sqrt{7}} \)
\( \frac{10}{2} \) \( \sqrt{\frac{21}{7}} \)
5 \( \sqrt{3} \)
If the ratio of home fans to visiting fans in a crowd is 2:1 and all 41,000 seats in a stadium are filled, how many home fans are in attendance?
| 25,600 | |
| 37,500 | |
| 24,000 | |
| 27,333 |
A ratio of 2:1 means that there are 2 home fans for every one visiting fan. So, of every 3 fans, 2 are home fans and \( \frac{2}{3} \) of every fan in the stadium is a home fan:
41,000 fans x \( \frac{2}{3} \) = \( \frac{82000}{3} \) = 27,333 fans.
| 1 | |
| 1.6 | |
| 3.2 | |
| 0.9 |
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