| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.43 |
| Score | 0% | 49% |
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 7 parts per hour. Yesterday the machine was shut down for 3 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 110.6 | |
| 101.5 | |
| 158.8 | |
| 136.7 |
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 7 = \( \frac{7 \times 7}{100} \) = \( \frac{49}{100} \) = 0.49 errors per hour
So, in an average hour, the machine will produce 7 - 0.49 = 6.51 error free parts.
The machine ran for 24 - 3 = 21 hours yesterday so you would expect that 21 x 6.51 = 136.7 error free parts were produced yesterday.
If the ratio of home fans to visiting fans in a crowd is 2:1 and all 37,000 seats in a stadium are filled, how many home fans are in attendance?
| 27,200 | |
| 24,667 | |
| 26,667 | |
| 32,000 |
A ratio of 2:1 means that there are 2 home fans for every one visiting fan. So, of every 3 fans, 2 are home fans and \( \frac{2}{3} \) of every fan in the stadium is a home fan:
37,000 fans x \( \frac{2}{3} \) = \( \frac{74000}{3} \) = 24,667 fans.
A circular logo is enlarged to fit the lid of a jar. The new diameter is 30% larger than the original. By what percentage has the area of the logo increased?
| 25% | |
| 20% | |
| 27\(\frac{1}{2}\)% | |
| 15% |
The area of a circle is given by the formula A = πr2 where r is the radius of the circle. The radius of a circle is its diameter divided by two so A = π(\( \frac{d}{2} \))2. If the diameter of the logo increases by 30% the radius (and, consequently, the total area) increases by \( \frac{30\text{%}}{2} \) = 15%
What is \( 2 \)\( \sqrt{125} \) - \( 8 \)\( \sqrt{5} \)
| 16\( \sqrt{625} \) | |
| -6\( \sqrt{0} \) | |
| 2\( \sqrt{5} \) | |
| 16\( \sqrt{5} \) |
To subtract these radicals together their radicands must be the same:
2\( \sqrt{125} \) - 8\( \sqrt{5} \)
2\( \sqrt{25 \times 5} \) - 8\( \sqrt{5} \)
2\( \sqrt{5^2 \times 5} \) - 8\( \sqrt{5} \)
(2)(5)\( \sqrt{5} \) - 8\( \sqrt{5} \)
10\( \sqrt{5} \) - 8\( \sqrt{5} \)
Now that the radicands are identical, you can subtract them:
10\( \sqrt{5} \) - 8\( \sqrt{5} \)\({b + c \over a} = {b \over a} + {c \over a}\) defines which of the following?
commutative property for multiplication |
|
distributive property for division |
|
commutative property for division |
|
distributive property for multiplication |
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, \({a^3 + 6a^2 \over a^2} = {a^3 \over a^2} + {6a^2 \over a^2} = a + 6\).