| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.08 |
| Score | 0% | 62% |
What is the greatest common factor of 20 and 64?
| 13 | |
| 4 | |
| 3 | |
| 9 |
The factors of 20 are [1, 2, 4, 5, 10, 20] and the factors of 64 are [1, 2, 4, 8, 16, 32, 64]. They share 3 factors [1, 2, 4] making 4 the greatest factor 20 and 64 have in common.
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 2 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 149.9 | |
| 146.3 | |
| 100.1 | |
| 133.8 |
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 - 2 = 22 hours yesterday so you would expect that 22 x 4.55 = 100.1 error free parts were produced yesterday.
The total water usage for a city is 10,000 gallons each day. Of that total, 21% is for personal use and 38% is for industrial use. How many more gallons of water each day is consumed for industrial use over personal use?
| 4,400 | |
| 2,600 | |
| 6,000 | |
| 1,700 |
38% of the water consumption is industrial use and 21% is personal use so (38% - 21%) = 17% more water is used for industrial purposes. 10,000 gallons are consumed daily so industry consumes \( \frac{17}{100} \) x 10,000 gallons = 1,700 gallons.
What is \( \frac{5y^5}{6y^4} \)?
| 1\(\frac{1}{5}\)y | |
| \(\frac{5}{6}\)y | |
| \(\frac{5}{6}\)y-1 | |
| \(\frac{5}{6}\)y9 |
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:
\( \frac{5y^5}{6y^4} \)
\( \frac{5}{6} \) y(5 - 4)
\(\frac{5}{6}\)y
If \( \left|x + 5\right| \) + 3 = 4, which of these is a possible value for x?
| -9 | |
| -7 | |
| -6 | |
| -1 |
First, solve for \( \left|x + 5\right| \):
\( \left|x + 5\right| \) + 3 = 4
\( \left|x + 5\right| \) = 4 - 3
\( \left|x + 5\right| \) = 1
The value inside the absolute value brackets can be either positive or negative so (x + 5) must equal + 1 or -1 for \( \left|x + 5\right| \) to equal 1:
| x + 5 = 1 x = 1 - 5 x = -4 | x + 5 = -1 x = -1 - 5 x = -6 |
So, x = -6 or x = -4.