| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.06 |
| Score | 0% | 61% |
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 6 parts per hour. Yesterday the machine was shut down for 7 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 88.3 | |
| 94.9 | |
| 117.6 | |
| 165.6 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{7}{100} \) x 6 = \( \frac{7 \times 6}{100} \) = \( \frac{42}{100} \) = 0.42 errors per hour
So, in an average hour, the machine will produce 6 - 0.42 = 5.58 error free parts.
The machine ran for 24 - 7 = 17 hours yesterday so you would expect that 17 x 5.58 = 94.9 error free parts were produced yesterday.
In a class of 22 students, 8 are taking German and 7 are taking Spanish. Of the students studying German or Spanish, 5 are taking both courses. How many students are not enrolled in either course?
| 12 | |
| 15 | |
| 11 | |
| 16 |
The number of students taking German or Spanish is 8 + 7 = 15. Of that group of 15, 5 are taking both languages so they've been counted twice (once in the German group and once in the Spanish group). Subtracting them out leaves 15 - 5 = 10 who are taking at least one language. 22 - 10 = 12 students who are not taking either language.
What is 7c7 x 4c4?
| 28c11 | |
| 28c3 | |
| 28c7 | |
| 28c4 |
To multiply terms with exponents, the base of both exponents must be the same. In this case they are so multiply the coefficients and add the exponents:
7c7 x 4c4
(7 x 4)c(7 + 4)
28c11
\({b + c \over a} = {b \over a} + {c \over a}\) defines which of the following?
commutative property for multiplication |
|
distributive property for division |
|
distributive property for multiplication |
|
commutative property for division |
The distributive property for division helps in solving expressions like \({b + c \over a}\). It specifies that the result of dividing a fraction with multiple terms in the numerator and one term in the denominator can be obtained by dividing each term individually and then totaling the results: \({b + c \over a} = {b \over a} + {c \over a}\). For example, \({a^3 + 6a^2 \over a^2} = {a^3 \over a^2} + {6a^2 \over a^2} = a + 6\).
Simplify \( \sqrt{32} \)
| 3\( \sqrt{4} \) | |
| 7\( \sqrt{2} \) | |
| 4\( \sqrt{2} \) | |
| 2\( \sqrt{4} \) |
To simplify a radical, factor out the perfect squares:
\( \sqrt{32} \)
\( \sqrt{16 \times 2} \)
\( \sqrt{4^2 \times 2} \)
4\( \sqrt{2} \)