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Each month, a new set of puzzles will be posted.  Come back next month for the solutions and a new set of puzzles, or subscribe to have them sent directly to you.

  1. How many complete turns does circle A make to rotate around the outside of circle B once if circle A is one-half the size of circle B. (Note: Diagram is not drawn to scale.)

  1. How many complete turns does circle A make to rotate around the inside of circle B once if circle A is one-half the size of circle B. (Note: Diagram is not drawn to scale.)

 

 

  1. To get a square photograph to fit into a rectangular frame, Brian had to trim a 1-inch strip from each of two opposite sides of the photo and a 2-inch strip from each of the other two sides. In all, he trimmed of 64 squire inches. What were the original dimensions of the photograph?

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Last month's solutions

MIND-Xpanders

  1. What is the number of degrees that the hour hand of a clock moves through between noon and 4:30 in the afternoon of the same day?
    Solution: 360º / 12 numbers = 30º and 30º x 4.5 numbers = 135º
  2. Raeanne takes 20 minutes to jog around the race track course once, and 25 minutes to jog around a second time. What is her average speed in miles per hour for the whole jog if the course is 3 miles long?
    Solution:
    Average speed = total distance / total time
    Total distance covered = 2 x 3 = 6 miles
    Total time = 20 + 25 = 45 minutes or 0.75 hours
    Average speed = 6 / 0.75 = 8 miles/hour
  3. Two equal circles are cut out of a rectangular paper card of dimensions 8 cm by 16 cm. The circles have a maximum radius possible. What is the area of the paper remaining (shadded area) after the circles have been cut out as shown? (note: use π = 3.14)

 

Solution:

The area remaining (or in gray) is the area of the rectangle minus 2 times the area of a circle

= (16 x 8) – 2 x (πr²), where r = 16/4 = 4,
then (128) – (2 x 3.14 x 16)
= 128 – 100.48
= 27.52 cm.

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