| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.93 |
| Score | 0% | 59% |
Which of the following is not a prime number?
7 |
|
5 |
|
2 |
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9 |
A prime number is an integer greater than 1 that has no factors other than 1 and itself. Examples of prime numbers include 2, 3, 5, 7, and 11.
If \( \left|a - 1\right| \) + 4 = 3, which of these is a possible value for a?
| 0 | |
| 15 | |
| -14 | |
| -7 |
First, solve for \( \left|a - 1\right| \):
\( \left|a - 1\right| \) + 4 = 3
\( \left|a - 1\right| \) = 3 - 4
\( \left|a - 1\right| \) = -1
The value inside the absolute value brackets can be either positive or negative so (a - 1) must equal - 1 or --1 for \( \left|a - 1\right| \) to equal -1:
| a - 1 = -1 a = -1 + 1 a = 0 | a - 1 = 1 a = 1 + 1 a = 2 |
So, a = 2 or a = 0.
A factor is a positive __________ that divides evenly into a given number.
fraction |
|
integer |
|
improper fraction |
|
mixed number |
A factor is a positive integer that divides evenly into a given number. For example, the factors of 8 are 1, 2, 4, and 8.
A machine in a factory has an error rate of 9 parts per 100. The machine normally runs 24 hours a day and produces 6 parts per hour. Yesterday the machine was shut down for 8 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 87.4 | |
| 69.8 | |
| 147.4 | |
| 123.5 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{9}{100} \) x 6 = \( \frac{9 \times 6}{100} \) = \( \frac{54}{100} \) = 0.54 errors per hour
So, in an average hour, the machine will produce 6 - 0.54 = 5.46 error free parts.
The machine ran for 24 - 8 = 16 hours yesterday so you would expect that 16 x 5.46 = 87.4 error free parts were produced yesterday.
What is \( 5 \)\( \sqrt{50} \) + \( 2 \)\( \sqrt{2} \)
| 27\( \sqrt{2} \) | |
| 7\( \sqrt{50} \) | |
| 10\( \sqrt{50} \) | |
| 7\( \sqrt{25} \) |
To add these radicals together their radicands must be the same:
5\( \sqrt{50} \) + 2\( \sqrt{2} \)
5\( \sqrt{25 \times 2} \) + 2\( \sqrt{2} \)
5\( \sqrt{5^2 \times 2} \) + 2\( \sqrt{2} \)
(5)(5)\( \sqrt{2} \) + 2\( \sqrt{2} \)
25\( \sqrt{2} \) + 2\( \sqrt{2} \)
Now that the radicands are identical, you can add them together:
25\( \sqrt{2} \) + 2\( \sqrt{2} \)