| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.10 |
| Score | 0% | 62% |
A machine in a factory has an error rate of 2 parts per 100. The machine normally runs 24 hours a day and produces 7 parts per hour. Yesterday the machine was shut down for 9 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 130.2 | |
| 102.9 | |
| 169.2 | |
| 79.1 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{2}{100} \) x 7 = \( \frac{2 \times 7}{100} \) = \( \frac{14}{100} \) = 0.14 errors per hour
So, in an average hour, the machine will produce 7 - 0.14 = 6.86 error free parts.
The machine ran for 24 - 9 = 15 hours yesterday so you would expect that 15 x 6.86 = 102.9 error free parts were produced yesterday.
If a rectangle is twice as long as it is wide and has a perimeter of 18 meters, what is the area of the rectangle?
| 50 m2 | |
| 18 m2 | |
| 98 m2 | |
| 8 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 18 meters so the equation becomes: 2w + 2h = 18.
Putting these two equations together and solving for width (w):
2w + 2h = 18
w + h = \( \frac{18}{2} \)
w + h = 9
w = 9 - h
From the question we know that h = 2w so substituting 2w for h gives us:
w = 9 - 2w
3w = 9
w = \( \frac{9}{3} \)
w = 3
Since h = 2w that makes h = (2 x 3) = 6 and the area = h x w = 3 x 6 = 18 m2
A bread recipe calls for 2\(\frac{1}{2}\) cups of flour. If you only have 1\(\frac{1}{4}\) cups, how much more flour is needed?
| 2\(\frac{1}{8}\) cups | |
| 1\(\frac{1}{4}\) cups | |
| 2\(\frac{1}{4}\) cups | |
| \(\frac{5}{8}\) cups |
The amount of flour you need is (2\(\frac{1}{2}\) - 1\(\frac{1}{4}\)) cups. Rewrite the quantities so they share a common denominator and subtract:
(\( \frac{20}{8} \) - \( \frac{10}{8} \)) cups
\( \frac{10}{8} \) cups
1\(\frac{1}{4}\) cups
What is the next number in this sequence: 1, 5, 9, 13, 17, __________ ?
| 16 | |
| 14 | |
| 22 | |
| 21 |
The equation for this sequence is:
an = an-1 + 4
where n is the term's order in the sequence, an is the value of the term, and an-1 is the value of the term before an. This makes the next number:
a6 = a5 + 4
a6 = 17 + 4
a6 = 21
What is \( \frac{-9z^8}{5z^4} \)?
| -1\(\frac{4}{5}\)z12 | |
| -1\(\frac{4}{5}\)z32 | |
| -\(\frac{5}{9}\)z12 | |
| -1\(\frac{4}{5}\)z4 |
To divide terms with exponents, the base of both exponents must be the same. In this case they are so divide the coefficients and subtract the exponents:
\( \frac{-9z^8}{5z^4} \)
\( \frac{-9}{5} \) z(8 - 4)
-1\(\frac{4}{5}\)z4