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Practice Math Questions

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1. What's the radius of the largest sphere that can be placed inside a cube of volume 64?

  • (A) 16
  • (B) 8
  • (C) 4pi
  • (D) 2pi
  • (E) 2
Cube

2. One side of this square is on the radius of the circle. The circle's radius is 6. What's the area of the blue region?

  • (A) 12pi
  • (B) 36pi
  • (C) 36pi - 12
  • (D) 36 - 9pi
  • (E) 36pi - 9
Square

3. The average of 12 consecutive even integers is 981. What's the highest of these integers?

  • (A) 988
  • (B) 989
  • (C) 990
  • (D) 991
  • (E) 992
  •  

Answers

1. What's the radius of the largest sphere that can be placed inside a cube of volume 64?

  • Answer is (E) 2
  •  
  • How to solve:
  •  
  • 1. If the cube's volume is 64, then each side is 4 wide.
  • Cube
  •  
  • 2. The largest circle or sphere that would fit inside this cube would have a diameter of 4.
  • Cube with circle
  •  
  • 3. The radius is half the diameter, so its radius would be 2.
  •  

2. One side of this square is on the center of the circle. The circle's radius is 6. What's the area of the blue region?

  • Answer is (D) 36 - 9pi
Square
  • How to solve:
  •  
  • 1. The area of the square is 36.
  • Square
  •  
  • 2. The area of the entire circle is 36pi.
  •  
  • Circle
  • Circle
  •  
  • 3. Only 1/4 of the circle is in the drawing. 1/4 of 36pi is 9pi.
  •  
  • Quarter circle
  •  
  •  
  • 4. Subtract the area of the quarter circle from the area of square.
  •  
  • Square
  •  
  • 5. The area of the blue region is 36 - 9pi
  •  
  • Answers will almost always be in terms of pi.
  •  

3. The average of 12 consecutive even integers is 981. What's the highest of these integers?

  • Answer is (E) 992
  •  
  •  
  • How to solve:
  •  
  • 1. There are 12 numbers, so we'll draw 12 spaces.
  • 12 Spaces
  •  
  • 2. The average is 981, so it goes right in the middle.
  • 981
  •  
  • 3. The numbers are consecutive even numbers, so we know what the next number is.
  • 982
  •  
  • 4. And from there, we know what all the other numbers are.
  • 992
  •  
  • 5. The highest is 992.
  •  

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