| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.39 |
| Score | 0% | 68% |
How many hours does it take a car to travel 250 miles at an average speed of 50 miles per hour?
| 9 hours | |
| 3 hours | |
| 2 hours | |
| 5 hours |
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 time:
time = \( \frac{\text{distance}}{\text{speed}} \)
time = \( \frac{250mi}{50mph} \)
5 hours
The __________ is the smallest positive integer that is a multiple of two or more integers.
greatest common factor |
|
least common multiple |
|
least common factor |
|
absolute value |
The least common multiple (LCM) is the smallest positive integer that is a multiple of two or more integers.
What is \( \frac{3}{8} \) x \( \frac{4}{5} \)?
| \(\frac{3}{10}\) | |
| 2\(\frac{2}{5}\) | |
| \(\frac{8}{25}\) | |
| \(\frac{2}{27}\) |
To multiply fractions, multiply the numerators together and then multiply the denominators together:
\( \frac{3}{8} \) x \( \frac{4}{5} \) = \( \frac{3 x 4}{8 x 5} \) = \( \frac{12}{40} \) = \(\frac{3}{10}\)
A machine in a factory has an error rate of 9 parts per 100. The machine normally runs 24 hours a day and produces 10 parts per hour. Yesterday the machine was shut down for 2 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 148.8 | |
| 200.2 | |
| 199.5 | |
| 155.5 |
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 10 = \( \frac{9 \times 10}{100} \) = \( \frac{90}{100} \) = 0.9 errors per hour
So, in an average hour, the machine will produce 10 - 0.9 = 9.1 error free parts.
The machine ran for 24 - 2 = 22 hours yesterday so you would expect that 22 x 9.1 = 200.2 error free parts were produced yesterday.
What is the greatest common factor of 56 and 60?
| 39 | |
| 21 | |
| 17 | |
| 4 |
The factors of 56 are [1, 2, 4, 7, 8, 14, 28, 56] and the factors of 60 are [1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60]. They share 3 factors [1, 2, 4] making 4 the greatest factor 56 and 60 have in common.