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jmc

counting and probability junior

Problem

Two circles with spinners at their centers are divided into three equal regions as shown. When both spinners are spun, what is the probability that the product of the two values is negative? Express your answer as a common fraction.
problem
Solution
There are nine possible products, as there are three different numbers upon which the first spinner could land and three different numbers upon which the second spinner could land. If the first spinner lands on or , the second spinner can land on either 2 or 4 to create a negative product, giving four possibilities. If the first spinner lands on the 5, the second spinner must land on the to create a negative product. Thus, there are five possible ways to create a negative product, so the probability that the product of the values is negative is .
Final answer
\frac{5}{9}