| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.36 |
| Score | 0% | 67% |
A machine in a factory has an error rate of 2 parts per 100. The machine normally runs 24 hours a day and produces 10 parts per hour. Yesterday the machine was shut down for 9 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 186.2 | |
| 114.7 | |
| 95.9 | |
| 147 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{2}{100} \) x 10 = \( \frac{2 \times 10}{100} \) = \( \frac{20}{100} \) = 0.2 errors per hour
So, in an average hour, the machine will produce 10 - 0.2 = 9.8 error free parts.
The machine ran for 24 - 9 = 15 hours yesterday so you would expect that 15 x 9.8 = 147 error free parts were produced yesterday.
Which of the following is not a prime number?
2 |
|
9 |
|
7 |
|
5 |
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.
What is (c5)4?
| c20 | |
| c | |
| 4c5 | |
| 5c4 |
To raise a term with an exponent to another exponent, retain the base and multiply the exponents:
(c5)4What is \( \frac{1}{9} \) x \( \frac{2}{8} \)?
| \(\frac{1}{36}\) | |
| \(\frac{1}{4}\) | |
| \(\frac{8}{21}\) | |
| \(\frac{1}{27}\) |
To multiply fractions, multiply the numerators together and then multiply the denominators together:
\( \frac{1}{9} \) x \( \frac{2}{8} \) = \( \frac{1 x 2}{9 x 8} \) = \( \frac{2}{72} \) = \(\frac{1}{36}\)
A menswear store is having a sale: "Buy one shirt at full price and get another shirt for 5% off." If Alex buys two shirts, each with a regular price of $21, how much money will he save?
| $1.05 | |
| $2.10 | |
| $7.35 | |
| $6.30 |
By buying two shirts, Alex will save $21 x \( \frac{5}{100} \) = \( \frac{$21 x 5}{100} \) = \( \frac{$105}{100} \) = $1.05 on the second shirt.