| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.26 |
| Score | 0% | 65% |
Simplify \( \frac{28}{48} \).
| \( \frac{9}{11} \) | |
| \( \frac{7}{13} \) | |
| \( \frac{2}{5} \) | |
| \( \frac{7}{12} \) |
To simplify this fraction, first find the greatest common factor between them. The factors of 28 are [1, 2, 4, 7, 14, 28] and the factors of 48 are [1, 2, 3, 4, 6, 8, 12, 16, 24, 48]. They share 3 factors [1, 2, 4] making 4 their greatest common factor (GCF).
Next, divide both numerator and denominator by the GCF:
\( \frac{28}{48} \) = \( \frac{\frac{28}{4}}{\frac{48}{4}} \) = \( \frac{7}{12} \)
A machine in a factory has an error rate of 6 parts per 100. The machine normally runs 24 hours a day and produces 7 parts per hour. Yesterday the machine was shut down for 3 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 120.3 | |
| 81.6 | |
| 138.2 | |
| 201.6 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{6}{100} \) x 7 = \( \frac{6 \times 7}{100} \) = \( \frac{42}{100} \) = 0.42 errors per hour
So, in an average hour, the machine will produce 7 - 0.42 = 6.58 error free parts.
The machine ran for 24 - 3 = 21 hours yesterday so you would expect that 21 x 6.58 = 138.2 error free parts were produced yesterday.
4! = ?
5 x 4 x 3 x 2 x 1 |
|
4 x 3 x 2 x 1 |
|
3 x 2 x 1 |
|
4 x 3 |
A factorial has the form n! and is the product of the integer (n) and all the positive integers below it. For example, 5! = 5 x 4 x 3 x 2 x 1 = 120.
What is 4\( \sqrt{2} \) x 6\( \sqrt{9} \)?
| 72\( \sqrt{2} \) | |
| 24\( \sqrt{9} \) | |
| 10\( \sqrt{18} \) | |
| 24\( \sqrt{11} \) |
To multiply terms with radicals, multiply the coefficients and radicands separately:
4\( \sqrt{2} \) x 6\( \sqrt{9} \)
(4 x 6)\( \sqrt{2 \times 9} \)
24\( \sqrt{18} \)
Now we need to simplify the radical:
24\( \sqrt{18} \)
24\( \sqrt{2 \times 9} \)
24\( \sqrt{2 \times 3^2} \)
(24)(3)\( \sqrt{2} \)
72\( \sqrt{2} \)
What is the least common multiple of 8 and 10?
| 80 | |
| 20 | |
| 69 | |
| 40 |
The first few multiples of 8 are [8, 16, 24, 32, 40, 48, 56, 64, 72, 80] and the first few multiples of 10 are [10, 20, 30, 40, 50, 60, 70, 80, 90]. The first few multiples they share are [40, 80] making 40 the smallest multiple 8 and 10 have in common.