| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.95 |
| Score | 0% | 59% |
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?
| 2 m2 | |
| 18 m2 | |
| 50 m2 | |
| 98 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
What is -5b7 - 3b7?
| -8b-7 | |
| -2b7 | |
| -2b49 | |
| -8b7 |
To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so subtract the coefficients and retain the base and exponent:
-5b7 - 3b7
(-5 - 3)b7
-8b7
Frank loaned Alex $1,200 at an annual interest rate of 7%. If no payments are made, what is the interest owed on this loan at the end of the first year?
| $84 | |
| $14 | |
| $24 | |
| $39 |
The yearly interest charged on this loan is the annual interest rate multiplied by the amount borrowed:
interest = annual interest rate x loan amount
i = (\( \frac{6}{100} \)) x $1,200
i = 0.07 x $1,200
i = $84
Which of these numbers is a factor of 32?
| 13 | |
| 4 | |
| 9 | |
| 16 |
The factors of a number are all positive integers that divide evenly into the number. The factors of 32 are 1, 2, 4, 8, 16, 32.
What is \( 9 \)\( \sqrt{28} \) + \( 4 \)\( \sqrt{7} \)
| 13\( \sqrt{7} \) | |
| 22\( \sqrt{7} \) | |
| 13\( \sqrt{196} \) | |
| 36\( \sqrt{4} \) |
To add these radicals together their radicands must be the same:
9\( \sqrt{28} \) + 4\( \sqrt{7} \)
9\( \sqrt{4 \times 7} \) + 4\( \sqrt{7} \)
9\( \sqrt{2^2 \times 7} \) + 4\( \sqrt{7} \)
(9)(2)\( \sqrt{7} \) + 4\( \sqrt{7} \)
18\( \sqrt{7} \) + 4\( \sqrt{7} \)
Now that the radicands are identical, you can add them together:
18\( \sqrt{7} \) + 4\( \sqrt{7} \)