| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.22 |
| Score | 0% | 64% |
Find the average of the following numbers: 15, 9, 15, 9.
| 15 | |
| 16 | |
| 7 | |
| 12 |
To find the average of these 4 numbers add them together then divide by 4:
\( \frac{15 + 9 + 15 + 9}{4} \) = \( \frac{48}{4} \) = 12
If \(\left|a\right| = 7\), which of the following best describes a?
a = 7 or a = -7 |
|
a = -7 |
|
none of these is correct |
|
a = 7 |
The absolute value is the positive magnitude of a particular number or variable and is indicated by two vertical lines: \(\left|-5\right| = 5\). In the case of a variable absolute value (\(\left|a\right| = 5\)) the value of a can be either positive or negative (a = -5 or a = 5).
A tiger in a zoo has consumed 132 pounds of food in 11 days. If the tiger continues to eat at the same rate, in how many more days will its total food consumtion be 168 pounds?
| 6 | |
| 1 | |
| 3 | |
| 7 |
If the tiger has consumed 132 pounds of food in 11 days that's \( \frac{132}{11} \) = 12 pounds of food per day. The tiger needs to consume 168 - 132 = 36 more pounds of food to reach 168 pounds total. At 12 pounds of food per day that's \( \frac{36}{12} \) = 3 more days.
What is the distance in miles of a trip that takes 7 hours at an average speed of 45 miles per hour?
| 320 miles | |
| 315 miles | |
| 70 miles | |
| 20 miles |
Average speed in miles per hour is the number of miles traveled divided by the number of hours:
speed = \( \frac{\text{distance}}{\text{time}} \)Solving for distance:
distance = \( \text{speed} \times \text{time} \)
distance = \( 45mph \times 7h \)
315 miles
What is \( 9 \)\( \sqrt{63} \) - \( 8 \)\( \sqrt{7} \)
| 72\( \sqrt{9} \) | |
| 19\( \sqrt{7} \) | |
| 72\( \sqrt{63} \) | |
| \( \sqrt{7} \) |
To subtract these radicals together their radicands must be the same:
9\( \sqrt{63} \) - 8\( \sqrt{7} \)
9\( \sqrt{9 \times 7} \) - 8\( \sqrt{7} \)
9\( \sqrt{3^2 \times 7} \) - 8\( \sqrt{7} \)
(9)(3)\( \sqrt{7} \) - 8\( \sqrt{7} \)
27\( \sqrt{7} \) - 8\( \sqrt{7} \)
Now that the radicands are identical, you can subtract them:
27\( \sqrt{7} \) - 8\( \sqrt{7} \)