6th Six Weeks Review Quiz

Explanation
If it takes 90 minutes to wash 20 vehicles, we can find the time it takes to wash 1 vehicle by dividing 90 minutes by 20 vehicles. This gives us 4.5 minutes per vehicle. To find the time it takes to wash 5 vehicles, we multiply 4.5 minutes by 5, which equals 22.5 minutes. Therefore, it takes 22.5 minutes to wash 5 vehicles at this rate.

Explanation
To find the value of x, we need to isolate the variable on one side of the equation. In this case, we can start by subtracting 6 from both sides of the equation: 3x + 6 - 6 = 15 - 6. Simplifying this gives us 3x = 9. To solve for x, we divide both sides of the equation by 3: (3x)/3 = 9/3. This simplifies to x = 3. Therefore, the value of x is 3.

Explanation
The volume of a rectangular prism is calculated by multiplying its length, width, and height. In this case, the length is given as 14 cm and the width is given as 6 cm. We can use the formula V = lwh, where V is the volume, l is the length, w is the width, and h is the height. We are given that the volume is 840 cubic cm. Plugging in the values, we get 840 = 14 * 6 * h. Solving for h, we find that the height is 10 cm.

Explanation
A cylinder has two parallel bases that are not polygons. The bases of a cylinder are circles, which are not polygons because they have curved sides. Therefore, a cylinder is the only option among the given choices that fits this description. A cone has one circular base and one curved surface, a prism has two parallel polygonal bases, and a pyramid has one polygonal base and triangular faces.

Explanation
38% of 850 is equivalent to 0.38 * 850 = 323. Therefore, there are 323 students in band & orchestra at Crownover Middle School.

Explanation
Eli is using a scale where 2 inches represents 25 feet. To find the length of the model train in inches, we need to determine how many times 25 feet fits into 60 feet. Since 25 feet is represented by 2 inches, we can set up a proportion: 25 feet is to 2 inches as 60 feet is to x inches. Cross-multiplying, we get 25 * x = 2 * 60. Solving for x, we find that x = 4.8 inches. Therefore, the length of the model train Eli should build is 4.8 inches.

Explanation
The equation r = 2k + 6 best represents the situation described in the question. This equation states that Robert's age, represented by r, is equal to 2 times Kayla's age, represented by k, plus 6. This aligns with the information given that Robert's age is 6 more than 2 times Kayla's age.

Explanation
Connor's parents asked him to save 2/5 of his allowance each week. To find the percentage, we need to convert 2/5 to a percentage. To do this, we divide 2 by 5 and then multiply by 100. This gives us 40%. Therefore, Connor's parents asked him to save 40% of his allowance.

Explanation
The approximate difference between the areas of the two circles can be found by subtracting the area of the smaller circle from the area of the larger circle. The formula for the area of a circle is A = πr^2, where A is the area and r is the radius.

For the larger circle with a radius of 20 inches, the area is approximately 1256 inches squared (A = π(20^2) = 3.14 * 400 = 1256).

For the smaller circle with a radius of 10 inches, the area is approximately 314 inches squared (A = π(10^2) = 3.14 * 100 = 314).

Subtracting the area of the smaller circle from the area of the larger circle gives us an approximate difference of 942 inches squared.

Explanation
The given expression involves addition, multiplication, and subtraction. According to the order of operations, we should perform the operations inside the parentheses first, which gives us (3 + 3) = 6. Then, we multiply 6 by 2, resulting in 12. Finally, we subtract 2 multiplied by 4, which is 8, from 12, giving us a final value of 4.