| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.35 |
| Score | 0% | 67% |
Which of the following is not an integer?
1 |
|
0 |
|
-1 |
|
\({1 \over 2}\) |
An integer is any whole number, including zero. An integer can be either positive or negative. Examples include -77, -1, 0, 55, 119.
Find the average of the following numbers: 11, 5, 12, 4.
| 8 | |
| 13 | |
| 7 | |
| 9 |
To find the average of these 4 numbers add them together then divide by 4:
\( \frac{11 + 5 + 12 + 4}{4} \) = \( \frac{32}{4} \) = 8
Convert 7,457,000 to scientific notation.
| 0.746 x 107 | |
| 7.457 x 106 | |
| 74.57 x 105 | |
| 7.457 x 10-5 |
A number in scientific notation has the format 0.000 x 10exponent. To convert to scientific notation, move the decimal point to the right or the left until the number is a decimal between 1 and 10. The exponent of the 10 is the number of places you moved the decimal point and is positive if you moved the decimal point to the left and negative if you moved it to the right:
7,457,000 in scientific notation is 7.457 x 106
Which of these numbers is a factor of 36?
| 28 | |
| 4 | |
| 2 | |
| 35 |
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.
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 9 parts per hour. Yesterday the machine was shut down for 4 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 115.2 | |
| 118.4 | |
| 167.4 | |
| 116.5 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{7}{100} \) x 9 = \( \frac{7 \times 9}{100} \) = \( \frac{63}{100} \) = 0.63 errors per hour
So, in an average hour, the machine will produce 9 - 0.63 = 8.37 error free parts.
The machine ran for 24 - 4 = 20 hours yesterday so you would expect that 20 x 8.37 = 167.4 error free parts were produced yesterday.