| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.64 |
| Score | 0% | 53% |
A machine in a factory has an error rate of 9 parts per 100. The machine normally runs 24 hours a day and produces 5 parts per hour. Yesterday the machine was shut down for 4 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 153.6 | |
| 89.3 | |
| 91 | |
| 176.7 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{9}{100} \) x 5 = \( \frac{9 \times 5}{100} \) = \( \frac{45}{100} \) = 0.45 errors per hour
So, in an average hour, the machine will produce 5 - 0.45 = 4.55 error free parts.
The machine ran for 24 - 4 = 20 hours yesterday so you would expect that 20 x 4.55 = 91 error free parts were produced yesterday.
If a rectangle is twice as long as it is wide and has a perimeter of 30 meters, what is the area of the rectangle?
| 2 m2 | |
| 98 m2 | |
| 128 m2 | |
| 50 m2 |
The area of a rectangle is width (w) x height (h). In this problem we know that the rectangle is twice as long as it is wide so h = 2w. The perimeter of a rectangle is 2w + 2h and we know that the perimeter of this rectangle is 30 meters so the equation becomes: 2w + 2h = 30.
Putting these two equations together and solving for width (w):
2w + 2h = 30
w + h = \( \frac{30}{2} \)
w + h = 15
w = 15 - h
From the question we know that h = 2w so substituting 2w for h gives us:
w = 15 - 2w
3w = 15
w = \( \frac{15}{3} \)
w = 5
Since h = 2w that makes h = (2 x 5) = 10 and the area = h x w = 5 x 10 = 50 m2
What is \( 2 \)\( \sqrt{175} \) + \( 3 \)\( \sqrt{7} \)
| 13\( \sqrt{7} \) | |
| 6\( \sqrt{175} \) | |
| 5\( \sqrt{25} \) | |
| 6\( \sqrt{25} \) |
To add these radicals together their radicands must be the same:
2\( \sqrt{175} \) + 3\( \sqrt{7} \)
2\( \sqrt{25 \times 7} \) + 3\( \sqrt{7} \)
2\( \sqrt{5^2 \times 7} \) + 3\( \sqrt{7} \)
(2)(5)\( \sqrt{7} \) + 3\( \sqrt{7} \)
10\( \sqrt{7} \) + 3\( \sqrt{7} \)
Now that the radicands are identical, you can add them together:
10\( \sqrt{7} \) + 3\( \sqrt{7} \)In a class of 33 students, 9 are taking German and 13 are taking Spanish. Of the students studying German or Spanish, 2 are taking both courses. How many students are not enrolled in either course?
| 13 | |
| 21 | |
| 27 | |
| 26 |
The number of students taking German or Spanish is 9 + 13 = 22. Of that group of 22, 2 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 22 - 2 = 20 who are taking at least one language. 33 - 20 = 13 students who are not taking either language.
A menswear store is having a sale: "Buy one shirt at full price and get another shirt for 5% off." If Damon buys two shirts, each with a regular price of $20, how much money will he save?
| $3.00 | |
| $1.00 | |
| $7.00 | |
| $6.00 |
By buying two shirts, Damon will save $20 x \( \frac{5}{100} \) = \( \frac{$20 x 5}{100} \) = \( \frac{$100}{100} \) = $1.00 on the second shirt.