| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.91 |
| Score | 0% | 58% |
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 10 parts per hour. Yesterday the machine was shut down for 5 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 115.9 | |
| 144.1 | |
| 176.7 | |
| 74.4 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{7}{100} \) x 10 = \( \frac{7 \times 10}{100} \) = \( \frac{70}{100} \) = 0.7 errors per hour
So, in an average hour, the machine will produce 10 - 0.7 = 9.3 error free parts.
The machine ran for 24 - 5 = 19 hours yesterday so you would expect that 19 x 9.3 = 176.7 error free parts were produced yesterday.
The __________ is the smallest positive integer that is a multiple of two or more integers.
least common factor |
|
absolute value |
|
greatest common factor |
|
least common multiple |
The least common multiple (LCM) is the smallest positive integer that is a multiple of two or more integers.
What is \( \frac{3}{8} \) ÷ \( \frac{3}{5} \)?
| \(\frac{3}{64}\) | |
| \(\frac{1}{7}\) | |
| \(\frac{1}{16}\) | |
| \(\frac{5}{8}\) |
To divide fractions, invert the second fraction and then multiply:
\( \frac{3}{8} \) ÷ \( \frac{3}{5} \) = \( \frac{3}{8} \) x \( \frac{5}{3} \)
To multiply fractions, multiply the numerators together and then multiply the denominators together:
\( \frac{3}{8} \) x \( \frac{5}{3} \) = \( \frac{3 x 5}{8 x 3} \) = \( \frac{15}{24} \) = \(\frac{5}{8}\)
Simplify \( \frac{32}{64} \).
| \( \frac{5}{12} \) | |
| \( \frac{3}{10} \) | |
| \( \frac{7}{18} \) | |
| \( \frac{1}{2} \) |
To simplify this fraction, first find the greatest common factor between them. The factors of 32 are [1, 2, 4, 8, 16, 32] and the factors of 64 are [1, 2, 4, 8, 16, 32, 64]. They share 6 factors [1, 2, 4, 8, 16, 32] making 32 their greatest common factor (GCF).
Next, divide both numerator and denominator by the GCF:
\( \frac{32}{64} \) = \( \frac{\frac{32}{32}}{\frac{64}{32}} \) = \( \frac{1}{2} \)
What is \( 9 \)\( \sqrt{75} \) - \( 6 \)\( \sqrt{3} \)
| 54\( \sqrt{225} \) | |
| 39\( \sqrt{3} \) | |
| 54\( \sqrt{25} \) | |
| 3\( \sqrt{225} \) |
To subtract these radicals together their radicands must be the same:
9\( \sqrt{75} \) - 6\( \sqrt{3} \)
9\( \sqrt{25 \times 3} \) - 6\( \sqrt{3} \)
9\( \sqrt{5^2 \times 3} \) - 6\( \sqrt{3} \)
(9)(5)\( \sqrt{3} \) - 6\( \sqrt{3} \)
45\( \sqrt{3} \) - 6\( \sqrt{3} \)
Now that the radicands are identical, you can subtract them:
45\( \sqrt{3} \) - 6\( \sqrt{3} \)