| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.49 |
| Score | 0% | 50% |
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 4 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 141.1 | |
| 92 | |
| 150.9 | |
| 153.6 |
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 - 4 = 20 hours yesterday so you would expect that 20 x 7.68 = 153.6 error free parts were produced yesterday.
Find the average of the following numbers: 16, 10, 17, 9.
| 13 | |
| 18 | |
| 16 | |
| 8 |
To find the average of these 4 numbers add them together then divide by 4:
\( \frac{16 + 10 + 17 + 9}{4} \) = \( \frac{52}{4} \) = 13
What is 5\( \sqrt{4} \) x 5\( \sqrt{3} \)?
| 25\( \sqrt{3} \) | |
| 25\( \sqrt{4} \) | |
| 10\( \sqrt{3} \) | |
| 50\( \sqrt{3} \) |
To multiply terms with radicals, multiply the coefficients and radicands separately:
5\( \sqrt{4} \) x 5\( \sqrt{3} \)
(5 x 5)\( \sqrt{4 \times 3} \)
25\( \sqrt{12} \)
Now we need to simplify the radical:
25\( \sqrt{12} \)
25\( \sqrt{3 \times 4} \)
25\( \sqrt{3 \times 2^2} \)
(25)(2)\( \sqrt{3} \)
50\( \sqrt{3} \)
What is \( 9 \)\( \sqrt{8} \) - \( 2 \)\( \sqrt{2} \)
| 18\( \sqrt{16} \) | |
| 18\( \sqrt{2} \) | |
| 16\( \sqrt{2} \) | |
| 18\( \sqrt{8} \) |
To subtract these radicals together their radicands must be the same:
9\( \sqrt{8} \) - 2\( \sqrt{2} \)
9\( \sqrt{4 \times 2} \) - 2\( \sqrt{2} \)
9\( \sqrt{2^2 \times 2} \) - 2\( \sqrt{2} \)
(9)(2)\( \sqrt{2} \) - 2\( \sqrt{2} \)
18\( \sqrt{2} \) - 2\( \sqrt{2} \)
Now that the radicands are identical, you can subtract them:
18\( \sqrt{2} \) - 2\( \sqrt{2} \)Which of the following statements about exponents is false?
b1 = b |
|
all of these are false |
|
b0 = 1 |
|
b1 = 1 |
A number with an exponent (be) consists of a base (b) raised to a power (e). The exponent indicates the number of times that the base is multiplied by itself. A base with an exponent of 1 equals the base (b1 = b) and a base with an exponent of 0 equals 1 ( (b0 = 1).