Try this beautiful problem from Probability from AMC 8, 2004.
Spinners A and B are spun. On each spinner, the arrow is equally likely to land on each number. What is the probability that the product of the two spinners' numbers is even?
probability
Equilly likely
Number counting
But try the problem first...
Answer: \(\frac{2}{3}\)
AMC-8, 2004 problem 21
Challenges and Thrills in Pre College Mathematics
First hint
Even number comes from multiplying an even and even, even and odd, or odd and even
Can you now finish the problem ..........
Second Hint
A odd number only comes from multiplying an odd and odd..............
can you finish the problem........
Final Step
We know that even number comes from multiplying an even and even, even and odd, or odd and even
and also a odd number only comes from multiplying an odd and odd,
There are few cases to find the probability of spinning two odd numbers from 1
Multiply the independent probabilities of each spinner getting an odd number together and subtract it from 1 we get.......
\(1 - \frac{2}{4} \times \frac{2}{3}\)= \(1 - \frac{1}{3} = \frac{2}{3} \)