| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.11 |
| Score | 0% | 62% |
A machine in a factory has an error rate of 4 parts per 100. The machine normally runs 24 hours a day and produces 8 parts per hour. Yesterday the machine was shut down for 8 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 81.9 | |
| 121 | |
| 122.9 | |
| 128 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{4}{100} \) x 8 = \( \frac{4 \times 8}{100} \) = \( \frac{32}{100} \) = 0.32 errors per hour
So, in an average hour, the machine will produce 8 - 0.32 = 7.68 error free parts.
The machine ran for 24 - 8 = 16 hours yesterday so you would expect that 16 x 7.68 = 122.9 error free parts were produced yesterday.
Solve for \( \frac{3!}{2!} \)
| 1680 | |
| 3 | |
| \( \frac{1}{30} \) | |
| \( \frac{1}{8} \) |
A factorial is the product of an integer and all the positive integers below it. To solve a fraction featuring factorials, expand the factorials and cancel out like numbers:
\( \frac{3!}{2!} \)
\( \frac{3 \times 2 \times 1}{2 \times 1} \)
\( \frac{3}{1} \)
3
What is \( 8 \)\( \sqrt{48} \) - \( 7 \)\( \sqrt{3} \)
| 56\( \sqrt{16} \) | |
| 56\( \sqrt{144} \) | |
| 25\( \sqrt{3} \) | |
| 56\( \sqrt{3} \) |
To subtract these radicals together their radicands must be the same:
8\( \sqrt{48} \) - 7\( \sqrt{3} \)
8\( \sqrt{16 \times 3} \) - 7\( \sqrt{3} \)
8\( \sqrt{4^2 \times 3} \) - 7\( \sqrt{3} \)
(8)(4)\( \sqrt{3} \) - 7\( \sqrt{3} \)
32\( \sqrt{3} \) - 7\( \sqrt{3} \)
Now that the radicands are identical, you can subtract them:
32\( \sqrt{3} \) - 7\( \sqrt{3} \)What is the distance in miles of a trip that takes 6 hours at an average speed of 45 miles per hour?
| 100 miles | |
| 325 miles | |
| 80 miles | |
| 270 miles |
Average speed in miles per hour is the number of miles traveled divided by the number of hours:
speed = \( \frac{\text{distance}}{\text{time}} \)Solving for distance:
distance = \( \text{speed} \times \text{time} \)
distance = \( 45mph \times 6h \)
270 miles
Which of these numbers is a factor of 36?
| 20 | |
| 8 | |
| 10 | |
| 4 |
The factors of a number are all positive integers that divide evenly into the number. The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36.