| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.24 |
| Score | 0% | 65% |
Which of the following is a mixed number?
\({a \over 5} \) |
|
\({7 \over 5} \) |
|
\({5 \over 7} \) |
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\(1 {2 \over 5} \) |
A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.
What is \( \frac{30\sqrt{25}}{6\sqrt{5}} \)?
| \(\frac{1}{5}\) \( \sqrt{\frac{1}{5}} \) | |
| 5 \( \sqrt{\frac{1}{5}} \) | |
| 5 \( \sqrt{5} \) | |
| \(\frac{1}{5}\) \( \sqrt{5} \) |
To divide terms with radicals, divide the coefficients and radicands separately:
\( \frac{30\sqrt{25}}{6\sqrt{5}} \)
\( \frac{30}{6} \) \( \sqrt{\frac{25}{5}} \)
5 \( \sqrt{5} \)
Which of the following statements about exponents is false?
b1 = 1 |
|
all of these are false |
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b0 = 1 |
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b1 = b |
A number with an exponent (be) consists of a base (b) raised to a power (e). The exponent indicates the number of times that the base is multiplied by itself. A base with an exponent of 1 equals the base (b1 = b) and a base with an exponent of 0 equals 1 ( (b0 = 1).
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 8 parts per hour. Yesterday the machine was shut down for 7 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 159.8 | |
| 213.4 | |
| 126.5 | |
| 82.8 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{7}{100} \) x 8 = \( \frac{7 \times 8}{100} \) = \( \frac{56}{100} \) = 0.56 errors per hour
So, in an average hour, the machine will produce 8 - 0.56 = 7.4399999999999995 error free parts.
The machine ran for 24 - 7 = 17 hours yesterday so you would expect that 17 x 7.4399999999999995 = 126.5 error free parts were produced yesterday.
What is 9y7 x 2y7?
| 11y14 | |
| 18y14 | |
| 11y7 | |
| 11y49 |
To multiply terms with exponents, the base of both exponents must be the same. In this case they are so multiply the coefficients and add the exponents:
9y7 x 2y7
(9 x 2)y(7 + 7)
18y14