1. If a year had two consecutive months with a Friday the 13th, what two months would they have to be? (Why?)
2. Find four consecutive whole numbers that add up to 178.
3. How many cards must be drawn from a standard deck of (52) playing cards to be sure that you have at least two cards from the same suit?
4. What part of a 1/2 square foot is a 1/2 foot square?
5. The average (mean) of three test scores is 74. What must the fourth test score be to increase the average (mean) to 78?
2 thoughts on “Brain Teasers 15-3”
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A couple of extension questions for number 2:
Why is it a harder problem to solve if you ask for 4 consecutive whole numbers to add to 177 (or pick any odd number)?
Can you find any even number of consecutive whole numbers (or change to consecutive integers) that adds to an odd number? When does this happen, when doesn’t this work? I wonder why.
How many different sets of consecutive INTEGERS sum to 75 (How do you know you found them all?)
Ah, yes, interesting questions, Kurt. I can see that this reminded you of one of our old Lab Exercises! 🙂
I will leave the questions for “Bonus” for any interested readers.