| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.88 |
| Score | 0% | 58% |
What is 2\( \sqrt{2} \) x 6\( \sqrt{2} \)?
| 12\( \sqrt{4} \) | |
| 8\( \sqrt{4} \) | |
| 12\( \sqrt{2} \) | |
| 24 |
To multiply terms with radicals, multiply the coefficients and radicands separately:
2\( \sqrt{2} \) x 6\( \sqrt{2} \)
(2 x 6)\( \sqrt{2 \times 2} \)
12\( \sqrt{4} \)
Now we need to simplify the radical:
12\( \sqrt{4} \)
12\( \sqrt{2^2} \)
(12)(2)
24
What is \( \frac{7x^7}{2x^2} \)?
| 3\(\frac{1}{2}\)x5 | |
| 3\(\frac{1}{2}\)x-5 | |
| 3\(\frac{1}{2}\)x\(\frac{2}{7}\) | |
| 3\(\frac{1}{2}\)x9 |
To divide terms with exponents, the base of both exponents must be the same. In this case they are so divide the coefficients and subtract the exponents:
\( \frac{7x^7}{2x^2} \)
\( \frac{7}{2} \) x(7 - 2)
3\(\frac{1}{2}\)x5
What is the greatest common factor of 16 and 20?
| 5 | |
| 4 | |
| 14 | |
| 2 |
The factors of 16 are [1, 2, 4, 8, 16] and the factors of 20 are [1, 2, 4, 5, 10, 20]. They share 3 factors [1, 2, 4] making 4 the greatest factor 16 and 20 have in common.
A machine in a factory has an error rate of 5 parts per 100. The machine normally runs 24 hours a day and produces 6 parts per hour. Yesterday the machine was shut down for 7 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 92.1 | |
| 83.7 | |
| 96.9 | |
| 98.7 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{5}{100} \) x 6 = \( \frac{5 \times 6}{100} \) = \( \frac{30}{100} \) = 0.3 errors per hour
So, in an average hour, the machine will produce 6 - 0.3 = 5.7 error free parts.
The machine ran for 24 - 7 = 17 hours yesterday so you would expect that 17 x 5.7 = 96.9 error free parts were produced yesterday.
What is \( \frac{4}{6} \) + \( \frac{8}{12} \)?
| 2 \( \frac{6}{12} \) | |
| 2 \( \frac{9}{12} \) | |
| 1\(\frac{1}{3}\) | |
| 1 \( \frac{2}{12} \) |
To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 6 are [6, 12, 18, 24, 30, 36, 42, 48, 54, 60] and the first few multiples of 12 are [12, 24, 36, 48, 60, 72, 84, 96]. The first few multiples they share are [12, 24, 36, 48, 60] making 12 the smallest multiple 6 and 12 share.
Next, convert the fractions so each denominator equals the lowest common multiple:
\( \frac{4 x 2}{6 x 2} \) + \( \frac{8 x 1}{12 x 1} \)
\( \frac{8}{12} \) + \( \frac{8}{12} \)
Now, because the fractions share a common denominator, you can add them:
\( \frac{8 + 8}{12} \) = \( \frac{16}{12} \) = 1\(\frac{1}{3}\)