| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.08 |
| Score | 0% | 62% |
Betty scored 85% on her final exam. If each question was worth 2 points and there were 200 possible points on the exam, how many questions did Betty answer correctly?
| 97 | |
| 85 | |
| 78 | |
| 76 |
Betty scored 85% on the test meaning she earned 85% of the possible points on the test. There were 200 possible points on the test so she earned 200 x 0.85 = 170 points. Each question is worth 2 points so she got \( \frac{170}{2} \) = 85 questions right.
What is the greatest common factor of 36 and 24?
| 12 | |
| 10 | |
| 13 | |
| 1 |
The factors of 36 are [1, 2, 3, 4, 6, 9, 12, 18, 36] and the factors of 24 are [1, 2, 3, 4, 6, 8, 12, 24]. They share 6 factors [1, 2, 3, 4, 6, 12] making 12 the greatest factor 36 and 24 have in common.
A bread recipe calls for 2\(\frac{1}{4}\) cups of flour. If you only have 1\(\frac{5}{8}\) cups, how much more flour is needed?
| 2\(\frac{1}{4}\) cups | |
| 2\(\frac{1}{2}\) cups | |
| 2 cups | |
| \(\frac{5}{8}\) cups |
The amount of flour you need is (2\(\frac{1}{4}\) - 1\(\frac{5}{8}\)) cups. Rewrite the quantities so they share a common denominator and subtract:
(\( \frac{18}{8} \) - \( \frac{13}{8} \)) cups
\( \frac{5}{8} \) cups
\(\frac{5}{8}\) cups
This property states taht the order of addition or multiplication does not mater. For example, 2 + 5 and 5 + 2 are equivalent.
distributive |
|
PEDMAS |
|
commutative |
|
associative |
The commutative property states that, when adding or multiplying numbers, the order in which they're added or multiplied does not matter. For example, 3 + 4 and 4 + 3 give the same result, as do 3 x 4 and 4 x 3.
A machine in a factory has an error rate of 8 parts per 100. The machine normally runs 24 hours a day and produces 9 parts per hour. Yesterday the machine was shut down for 7 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 140.8 | |
| 131.6 | |
| 96.6 | |
| 156.2 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{8}{100} \) x 9 = \( \frac{8 \times 9}{100} \) = \( \frac{72}{100} \) = 0.72 errors per hour
So, in an average hour, the machine will produce 9 - 0.72 = 8.28 error free parts.
The machine ran for 24 - 7 = 17 hours yesterday so you would expect that 17 x 8.28 = 140.8 error free parts were produced yesterday.