Prime Factor Math Circle 2012-2013
Elementary School Circle 1 (Grades 3-4). Problem Set 9
1. The weight of a honeydew melon equals the weight of half of a
honeydew melon plus 2 pounds. How much does a honeydew melon weigh?
2. The weight of 2 cold coins equals the weight of a third of a coin, plus
5 ounces. How much does a coin weigh?
3. There are 5 rubies, 13 sapphires and 10 diamonds in a dark cave. What is the smallest
number of stones you need to grab to make sure you have:
a. Two stones of a same kind
b. Three stones of a same kind
c. Two diamonds
d. Three rubies
4. Come up with a word that would look the same as its
reflection in a mirror placed below this word. (Remember
that not too many words behave like this. Look at the word
BREAD, for example. This word and its reflection look
differetnly - see the picture.)
© 2012 Prime Factor Math Circle
BREAD
Prime Factor Math Circle 2012-2013
5. Inside the angle below, draw boys and balls in such a way that, using 2 mirrors, you’d see
4 boys and 1 ball.
6. Inside the angle below, draw several girls in such a way that, using 2 mirrors, you’d see 6
girls.
© 2012 Prime Factor Math Circle